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18C Electrode Potentials 459 Com H2 gas pH2 = 1.00 atm + Salt bridge Cd aH+ = 1.00 aCd2+ = 1.00 Figure 18-8 Measurement of the standard electrode potential for Cd21 2e2 Cd(s) 21 the Cd/Cd21 couple is by convention given a negative sign, and ECd /Cd 20.403 V Because the cell potential is negative, the spontaneous cell reaction is not the reaction as written (that is, oxidation on the left and reduction on the right) Rather, the spontaneous reaction is in the opposite direction Cd(s) 2H1 Cd21 H2(g) A zinc electrode immersed in a solution having a zinc ion activity of unity develops a potential of 20.763 V when it is the right-hand electrode paired with a standard 21 hydrogen electrode on the left Thus, we can write EZn /Zn 20.763 V The standard electrode potentials for the four half-cells just described can be arranged in the following order: Half-Reaction Ag1 1e2 Ag(s) 2H1 12e2 H2(g) Cd21 12e2 Cd(s) Zn21 12e2 Zn(s) Standard Electrode Potential, V 10.799 0.000 20.403 20.763 The magnitudes of these electrode potentials indicate the relative strength of the four ionic species as electron acceptors (oxidizing agents), that is, in decreasing strength, Ag1 H1 Cd21 Zn21 18C-4 Additional Implications of the Iupac Sign Convention The sign convention described in the previous section was adopted at the IUPAC meeting in Stockholm in 1953 and is now accepted internationally Prior to this Unless otherwise noted, all content on this page is © Cengage Learning Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 460 chapter 18 Introduction to Electrochemistry An electrode potential is by definition a reduction potential An oxidation potential is the potential for the half-reaction written in the opposite way The sign of an oxidation potential is, therefore, opposite that for a reduction potential, but the magnitude is the same agreement, chemists did not always use the same convention, and this inconsistency was the cause of controversy and confusion in the development and routine use of electrochemistry Any sign convention must be based on expressing half-cell processes in a single way—either as oxidations or as reductions According to the IUPAC convention, the term “electrode potential” (or, more exactly, “relative electrode potential”) is reserved exclusively to describe half-reactions written as reductions There is no objection to the use of the term “oxidation potential” to indicate a process written in the opposite sense, but it is not proper to refer to such a potential as an electrode potential The sign of an electrode potential is determined by the sign of the half-cell in question when it is coupled to a standard hydrogen electrode When the half-cell of interest exhibits a positive potential versus the SHE (see Figure 18-7), it will behave spontaneously as the cathode when the cell is discharging When the half-cell of interest is negative versus the SHE (see Figure 18-8), it will behave spontaneously as the anode when the cell is discharging The IUPAC sign convention is based on the actual sign of the half-cell of interest when it is part of a cell containing the standard hydrogen electrode as the other half-cell ❯ 18C-5 Effect of Concentration on Electrode Potentials: The Nernst Equation An electrode potential is a measure of the extent to which the concentrations of the species in a half-cell differ from their equilibrium values For example, there is a greater tendency for the process Ag1 e2 Ag(s) to occur in a concentrated solution of silver(I) than in a dilute solution of that ion It follows that the magnitude of the electrode potential for this process must also become larger (more positive) as the silver ion concentration of a solution is increased We now examine the quantitative relationship between concentration and electrode potential Consider the reversible half-reaction The meanings of the bracketed terms in Equations 18-11 and 18-12 are, for a solute A [A] molar concentration and for a gas B [B] pB partial pressure in atmospheres If one or more of the species appearing in Equation 18-11 is a pure liquid, pure solid, or the solvent present in excess, then no bracketed term for this species appears in the quotient because the activities of these are unity ❯ aA bB ne2 c C d D (18-10) where the capital letters represent formulas for the participating species (atoms, molecules, or ions), e2 represents the electrons, and the lower case italic letters indicate the number of moles of each species appearing in the half-reaction as it has been written The electrode potential for this process is given by the equation E E0 RT [ C ] c [ D ] d ln [ A ]a [ B ]b nF (18-11) where E 0 the standard electrode potential, which is characteristic for each half-reaction R the ideal gas constant, 8.314 J K21 mol21 T temperature, K n number of moles of electrons that appears in the half-reaction for the electrode process as written F the faraday 96,485 C (coulombs) per mole of electrons ln natural logarithm 2.303 log Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 18C Electrode Potentials 461 © Bettmann/CORBIS Walther Nernst (1864–1941) received the 1920 Nobel Prize in chemistry for his numerous contributions to the field of chemical thermodynamics Nernst (right) is seen here in his laboratory in 1921 If we substitute numerical values for the constants, convert to base 10 logarithms, and specify 25°C for the temperature, we get E E0 [ C ]c [ D ]d 0.0592 log n [ A ]a [ B ]b (18-12) Strictly speaking, the letters in brackets represent activities, but we will usually follow the practice of substituting molar concentrations for activities in most calculations Thus, if some participating species A is a solute, [A] is the concentration of A in moles per liter If A is a gas, [A] in Equation 18-12 is replaced by pA, the partial pressure of A in atmospheres If A is a pure liquid, a pure solid, or the solvent, its activity is unity, and no term for A is included in the equation The rationale for these assumptions is the same as that described in Section 9B-2, which deals with equilibriumconstant expressions Equation 18-12 is known as the Nernst equation in honor of the German chemist Walther Nernst, who was responsible for its development EXAMPLE 18-2 Typical half-cell reactions and their corresponding Nernst expressions follow (1) Zn21 2e2 Zn(s) E E 0.0592 log [ Zn21 ] No term for elemental zinc is included in the logarithmic term because it is a pure second phase (solid) Thus, the electrode potential varies linearly with the logarithm of the reciprocal of the zinc ion concentration (2) Fe31 e2 Fe21(s) E E [ Fe21 ] 0.0592 log [ Fe31 ] The potential for this couple can be measured with an inert metallic electrode immersed in a solution containing both iron species The potential depends on the logarithm of the ratio between the molar concentrations of these ions Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 462 chapter 18 Introduction to Electrochemistry (3) 2H1 2e2 H2( g) E E pH2 0.0592 log [ H1 ] 2 In this example, ph2 is the partial pressure of hydrogen (in atmospheres) at the surface of the electrode Usually, its value will be the same as atmospheric pressure (4) MnO42 5e2 8H1 Mn21 4H2O E E0 [ Mn21 ] 0.0592 log [ MnO42 ][ H1 ]8 In this situation, the potential depends not only on the concentrations of the manganese species but also on the pH of the solution The Nernst expression in part (5) of Example 18-2 requires an excess of solid AgCl so that the solution is saturated with the compound at all times ❯ (5) AgCl(s) e2 Ag(s) Cl2 E E 0.0592 log [ Cl2 ] This half-reaction describes the behavior of a silver electrode immersed in a chloride solution that is saturated with AgCl To ensure this condition, an excess of the solid AgCl must always be present Note that this electrode reaction is the sum of the following two reactions: AgCl(s) Ag1 Cl2 Ag1 e2 Ag(s) Note also that the electrode potential is independent of the amount of AgCl present as long as there is at least some present to keep the solution saturated 18C-6 The Standard Electrode Potential, E 0 The standard electrode potential for a half-reaction, E 0, is defined as the electrode potential when all reactants and products of a half-reaction are at unit activity When we look carefully at Equations 18-11 and 18-12, we see that the constant E 0 is the electrode potential whenever the concentration quotient (actually, the activity quotient) has a value of This constant is by definition the standard electrode potential for the half-reaction Note that the quotient is always equal to when the activities of the reactants and products of a half-reaction are unity The standard electrode potential is an important physical constant that provides quantitative information regarding the driving force for a half-cell reaction.2 The important characteristics of these constants are the following: The standard electrode potential is a relative quantity in the sense that it is the potential of an electrochemical cell in which the reference electrode (left-hand electrode) is the standard hydrogen electrode, whose potential has been assigned a value of 0.000 V The standard electrode potential for a half-reaction refers exclusively to a reduction reaction, that is, it is a relative reduction potential The standard electrode potential measures the relative force tending to drive the half-reaction from a state in which the reactants and products are at unit activity to a state in which the reactants and products are at their equilibrium activities relative to the standard hydrogen electrode For further reading on standard electrode potentials, see R G Bates, in Treatise on Analytical Chemistry, 2nd ed., I M Kolthoff and P J Elving, eds., Part I, Vol 1, Ch 13, New York: Wiley, 1978 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 18C Electrode Potentials 463 The standard electrode potential is independent of the number of moles of reactant and product shown in the balanced half-reaction Thus, the standard electrode potential for the half-reaction Fe31 e2 Fe21 E 0 10.771 V does not change if we choose to write the reaction as 5Fe31 5e2 5Fe21 E 0 10.771 V Note, however, that the Nernst equation must be consistent with the half-reaction as written For the first case, it will be E 0.771 [ Fe21 ] 0.0592 log [ Fe31 ] and for the second E 0.771 [ Fe21 ] [ Fe21 ] 0.0592 0.0592 log 0.771 log a b [ Fe31 ] [ Fe31 ] 5 [ Fe21 ] 0.0592 0.771 log [ Fe31 ] 5 A positive electrode potential indicates that the half-reaction in question is spontaneous with respect to the standard hydrogen electrode half-reaction In other words, the oxidant in the half-reaction is a stronger oxidant than is hydrogen ion A negative sign indicates just the opposite The standard electrode potential for a half-reaction is temperature dependent that the two log terms have ❮ Note identical values, that is, [ Fe21 ] 0.0592 log [ Fe31 ] 5 [ Fe21 ] 0.0592 log [ Fe31 ] 5 [ Fe21 ] 0.0592 log a b [ Fe31 ] Standard electrode potential data are available for an enormous number of halfreactions Many have been determined directly from electrochemical measurements Others have been computed from equilibrium studies of oxidation/reduction systems and from thermochemical data associated with such reactions Table 18-1 contains standard electrode potential data for several half-reactions that we will be considering in the pages that follow A more extensive listing is found in Appendix 5.3 Table 18-1 and Appendix illustrate the two common ways for tabulating standard potential data In Table 18-1, potentials are listed in decreasing numerical order As a consequence, the species in the upper left part are the most effective electron acceptors, as evidenced by their large positive values They are therefore the strongest oxidizing agents As we proceed down the left side of such a table, each succeeding species is less effective as an electron acceptor than the one above it The half-cell reactions at the bottom of the table have little or no tendency to take place as they are written On the other hand, they tend to occur in the opposite sense The most effective reducing agents, then, are those species that appear in the lower right portion of the table Comprehensive sources for standard electrode potentials include A J Bard, R Parsons, and J Jordan, eds., Standard Electrode Potentials in Aqueous Solution, New York: Dekker, 1985; G Milazzo, S Caroli, and V K Sharma, Tables of Standard Electrode Potentials, New York: Wiley-Interscience, 1978; M S Antelman and F J Harris, Chemical Electrode Potentials, New York: Plenum Press, 1982 Some compilations are arranged alphabetically by element; others are tabulated according to the value of E Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 464 chapter 18 Based on the E values in Table 18-1 for Fe31 and I32, which species would you expect to predominate in a solution produced by mixing iron(III) and iodide ions? See color plate 12 Introduction to Electrochemistry TABLE 18-1 ❯ Standard Electrode Potentials* E 0 at 25°C, V Reaction Cl2(g) 2e2 2Cl2 O2(g) 4H1 4e2 2H2O Br2(aq) 2e2 2Br2 Br2(l ) 2e2 2Br2 Ag1 e2 Ag(s) Fe31 e2 Fe21 I321 2e2 3I2 Cu21 2e2 Cu(s) UO221 4H1 2e2 U41 2H2O Hg2Cl2(s) 2e2 2Hg(l ) 2Cl2 AgCl(s) e2 Ag(s)1Cl2 Ag(S2O3)232 e2 Ag(s) 2S2O322 2H1 2e2 H2(g) AgI(s) e2 Ag(s) I2 PbSO4 2e2 Pb(s) SO422 Cd21 2e2 Cd(s) Zn21 2e2 Zn(s) 11.359 11.229 11.087 11.065 10.799 10.771 10.536 10.337 10.334 10.268 10.222 10.017 0.000 20.151 20.350 20.403 20.763 *See Appendix for a more extensive list Feature 18-4 Sign Conventions in the Older Literature Reference works, particularly those published before 1953, often contain tabulations of electrode potentials that are not in accord with the IUPAC recommendations For example, in a classic source of standard-potential data compiled by Latimer,4 one finds Zn(s) Zn21 2e2 E 10.76 V Cu(s) Cu21 2e2 E 10.34 V To convert these oxidation potentials to electrode potentials as defined by the IUPAC convention, we must mentally (1) express the half-reactions as reductions and (2) change the signs of the potentials The sign convention used in a tabulation of electrode potentials may not be explicitly stated This information can be deduced, however, by noting the direction and sign of the potential for a familiar half-reaction If the sign agrees with the IUPAC convention, the table can be used as is If not, the signs of all of the data must be reversed For example, the reaction O2( g) 4H1 4e2 2H2O E 11.229 V occurs spontaneously with respect to the standard hydrogen electrode and thus carries a positive sign If the potential for this half-reaction is negative in a table, it and all the other potentials should be multiplied by 21 W M Latimer, The Oxidation States of the Elements and Their Potentials in Aqueous Solutions, 2nd ed Englewood Cliffs, NJ: Prentice-Hall, 1952 Unless otherwise noted, all content on this page is © Cengage Learning Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 18C Electrode Potentials 465 Compilations of electrode-potential data, such as that shown in Table 18-1, provide chemists with qualitative insights into the extent and direction of electrontransfer reactions For example, the standard potential for silver(I) (10.799 V) is more positive than that for copper(II) (10.337 V) We therefore conclude that a piece of copper immersed in a silver(I) solution will cause the reduction of that ion and the oxidation of the copper On the other hand, we would expect no reaction if we place a piece of silver in a copper(II) solution In contrast to the data in Table 18-1, standard potentials in Appendix are arranged alphabetically by element to make it easier to locate data for a given electrode reaction Systems Involving Precipitates or Complex Ions In Table 18-1, we find several entries involving Ag(I) including Ag1 e2 Ag(s) EAg /Ag 10.799 V AgCl(s) e2 Ag(s) Cl2 EAgCl/Ag 10.222 V Ag(S2O3)232 e2 Ag(s) 2S2O322 32 EAg(S 10.017 V 2O3)2 /Ag Each gives the potential of a silver electrode in a different environment Let us see how the three potentials are related The Nernst expression for the first half-reaction is E EAg /Ag 0.0592 log [ Ag1 ] If we replace [Ag1] with Ksp/[Cl2], we obtain E EAg /Ag [ Cl2 ] 0.0592 log EAg /Ag 0.0592 log Ksp 0.0592 log [ Cl ] Ksp By definition, the standard potential for the second half-reaction is the potential where [Cl2] 1.00 That is, when [Cl2] 1.00, E EAgCl/Ag Substituting these values gives 0 210 EAgCl/Ag EAg 0.0592 log (1.00) /Ag 0.0592 log 1.82 10 0.799 (20.577) 0.000 0.222 V Figure 18-9 shows the measurement of the standard electrode potential for the Ag/AgCl electrode If we proceed in the same way, we can obtain an expression for the standard electrode potential for the reduction of the thiosulfate complex of silver ion depicted in the third equilibrium shown at the start of this section In this case, the standard potential is given by 0 32 EAg(S EAg /Ag 0.0592 log b2 2O3)2 /Ag (18-13) Derive Equation ❮ CHALLENGE: 18-13 where b2 is the formation constant for the complex That is, b2 [ Ag(S2O3)232 ] [ Ag1 ][ S2O322 ] Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 466 chapter 18 Introduction to Electrochemistry Com H2 gas pH2 = 1.00 atm + Salt bridge Ag KCl solution saturated with AgCl Figure 18-9 Measurement of the standard electrode potential for an Ag/AgCl electrode aH+ = 1.00 AgCl(s) aCl– = 1.00 EXAMPLE 18-3 Calculate the electrode potential of a silver electrode immersed in a 0.0500 M 0 solution of NaCl using (a) E Ag /Ag 0.799 V and (b) E AgCl/Ag 0.222 V Solution EAg /Ag 10.799 V (a) Ag1 e2 Ag(s) The Ag1 concentration of this solution is given by [ Ag1 ] Ksp [ Cl2 ] 1.82 10210 3.64 1029 M 0.0500 Substituting into the Nernst expression gives E 0.799 0.0592 log 0.299 V 3.64 1029 (b) We may write this last equation as E 0.222 0.0592 log [ Cl ] 0.222 0.0592 log 0.0500 0.299 Feature 18-5 Why Are There Two Electrode Potentials for Br2 in Table 18-1? In Table 18-1, we find the following data for Br2: Br2(aq) 2e2 2Br2 E 0 11.087 V Br2(l ) 2e2 2Br2 E 0 11.065 V Unless otherwise noted, all content on this page is © Cengage Learning Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 18C Electrode Potentials 467 The second standard potential applies only to a solution that is saturated with Br2 and not to undersaturated solutions You should use 1.065 V to calculate the electrode potential of a 0.0100 M solution of KBr that is saturated with Br2 and in contact with an excess of the liquid In such a case, E 1.065 1.065 0.0592 0.0592 log [ Br2 ] 1.065 log (0.0100)2 2 0.0592 (24.00) 1.183 V In this calculation, no term for Br2 appears in the logarithmic term because it is a pure liquid present in excess (unit activity) The standard electrode potential shown in the first entry for Br2(aq) is hypothetical because the solubility of Br2 at 25°C is only about 0.18 M Thus, the recorded value of 1.087 V is based on a system that—in terms of our definition of E 0—cannot be realized experimentally Nevertheless, the hypothetical potential does permit us to calculate electrode potentials for solutions that are undersaturated in Br2 For example, if we wish to calculate the electrode potential for a solution that was 0.0100 M in KBr and 0.00100 M in Br2, we would write E 1.087 1.087 [ Br2 ] (0.0100)2 0.0592 0.0592 log 1.087 log [ Br2(aq) ] 2 0.00100 0.0592 log 0.100 1.117 V 18C-7 Limitations to the Use of Standard Electrode Potentials We will use standard electrode potentials throughout the rest of this text to calculate cell potentials and equilibrium constants for redox reactions as well as to calculate data for redox titration curves You should be aware that such calculations sometimes lead to results that are significantly different from those you would obtain in the laboratory There are two main sources of these differences: (1) the necessity of using concentrations in place of activities in the Nernst equation and (2) failure to take into account other equilibria such as dissociation, association, complex formation, and solvolysis Measurement of electrode potentials can allow us to investigate these equilibria and determine their equilibrium constants, however Use of Concentrations Instead of Activities Most analytical oxidation/reduction reactions are carried out in solutions that have such high ionic strengths that activity coefficients cannot be obtained via the DebyeHückel equation (see Equation 10-5, Section 10B-2) Significant errors may result, however, if concentrations are used in the Nernst equation rather than activities For example, the standard potential for the half-reaction Fe31 e2 Fe21 E 0 10.771 V is 10.771 V When the potential of a platinum electrode immersed in a solution that is 1024 M in iron(III) ion, iron(II) ion, and perchloric acid is measured against a standard hydrogen electrode, a reading of close to 10.77 V is obtained, as predicted by theory If, however, perchloric acid is added to this mixture until the acid Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 468 chapter 18 Introduction to Electrochemistry concentration is 0.1 M, the potential is found to decrease to about 10.75 V This difference is attributable to the fact that the activity coefficient of iron(III) is considerably smaller than that of iron(II) (0.4 versus 0.18) at the high ionic strength of the 0.1 M perchloric acid medium (see Table 10-2 page 242) As a consequence, the ratio of activities of the two species ([Fe21]/[Fe31]) in the Nernst equation is greater than unity, a condition that leads to a decrease in the electrode potential In M HClO4, the electrode potential is even smaller (≈ 0.73 V) Effect of Other Equilibria The following further complicate application of standard electrode potential data to many systems of interest in analytical chemistry: association, dissociation, complex formation, and solvolysis equilibria of the species that appear in the Nernst equation These phenomena can be taken into account only if their existence is known and appropriate equilibrium constants are available More often than not, neither of these requirements is met and significant discrepancies arise For example, the presence of M hydrochloric acid in the iron(II)/iron(III) mixture we have just discussed leads to a measured potential of 10.70 V, while in M sulfuric acid, a potential of 10.68 V is observed, and in a M phosphoric acid, the potential is 10.46 V In each of these cases, the iron(II)/iron(III) activity ratio is larger because the complexes of iron(III) with chloride, sulfate, and phosphate ions are more stable than those of iron(II) In these cases, the ratio of the species concentrations, [Fe21]/[Fe31], in the Nernst equation is greater than unity, and the measured potential is less than the standard potential If formation constants for these complexes were available, it would be possible to make appropriate corrections Unfortunately, such data are often not available, or if they are, they are not very reliable A formal potential is the electrode potential when the ratio of analytical concentrations of reactants and products of a half-reaction are exactly 1.00 and the molar concentrations of any other solutes are specified To distinguish the formal potential from the standard electrode potential a prime symbol is added to E Formal Potentials Formal potentials are empirical potentials that compensate for the types of activity and competing equilibria effects that we have just described The formal potential E 09of a system is the potential of the half-cell with respect to the standard hydrogen electrode measured under conditions such that the ratio of analytical concentrations of reactants and products as they appear in the Nernst equation is exactly unity and the concentrations of other species in the system are all carefully specified For example, the formal potential for the half-reaction Ag1 e2 Ag(s) E 09 0.792 V in M HClO4 could be obtained by measuring the potential of the cell shown in Figure 18-10 Here, the right-hand electrode is a silver electrode immersed in a solution that is 1.00 M in AgNO3 and 1.00 M in HClO4 The reference electrode on the left is a standard hydrogen electrode This cell has a potential of 10.792 V, which is the formal potential of the Ag1/Ag couple in 1.00 M HClO4 Note that the standard potential for this couple is 10.799 V Formal potentials for many half-reactions are listed in Appendix Note that there are large differences between the formal and standard potentials for some halfreactions For example, the formal potential for Fe(CN)632 e2 Fe(CN)642 E 10.36 V is 0.72 V in M perchloric or sulfuric acids, which is 0.36 V greater than the standard electrode potential for the half-reaction The reason for this difference is that in the presence of high concentrations of hydrogen ion, hexacyanoferrate(II) ions (Fe(CN)642), and hexacyanoferrate(III) ions (Fe(CN)632) combine with one or more protons to form hydrogen hexacyanoferrate(II) and hydrogen hexacyanoferrate(III) Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-10 Index Figures of merit, for analytical methods, 186–191 Film thickness, 901 Filter paper ashing, 33 defined, 29 folding and seating, 32 preparation of, 31–32 transferring to crucible, 32–33 Filter photometers, 750 Filterability crystalline precipitates, 286 digestion and, 286 of precipitates, 281–283 Filtration directions for, 31–34 media comparison, 29 precipitates, 30–34 of solids, 28–34 vacuum, 34 First-order reactions, 826s mathematics describing, 822–824 pseudo, 822 rate law for, 821–824 Fixed-time methods, 838–839 Flame atomic absorption defined, 795 detection limits and accuracy, 796 quantitative analysis, 795 quantitative measurements, 795 Flame atomizers defined, 781 detection limits, 784t laminar flow burners, 782 primary combustion zone, 782 spray chamber, 781 Flame ionization detector (FID), 892–893 Flames absorption spectra, 783–784 in atomic spectroscopy, 783t emission spectra, 783–784 ionization in, 784 properties of, 782–783 temperature, effects of, 783 Flash evaporation, 852 Flasks, volumetric, 37–38, 42–43 Flexures, 20 Flow patterns, 621 Flow-injection analysis (FIA) defined, 166 flow reversal, 166 illustrated, 167 miniaturized, 167 sampling error determination by, 993–996 Flow-injection apparatus, 747 Flow-injection techniques, 746 Fluorescence applications of methods, 766–769 atomic, 678 bands, 762 defined, 760 emission by, 678–679 immunoassay, 275 instrumentation, 765–766 intensity, concentration effect on, 764 molecular, 678 probe use in neurobiology, 767 quantum yield, 763 resonance, 678 spectra, 762, 775 Stokes-shifted, 762 structural rigidity, 763 structure and, 763 substitution effects on, 764t temperature and solvent effects, 763 Fluorescence spectroscopy, 656 Fluorescent species, 763 Fluoride ion, direct potentiometric determination of, 1031–1032 Fluorometer, 765 Fluxes common, 985t decomposition with, 984–985 defined, 984 fusion procedure, 984 types of, 984–985 Forced convection, 585 Formal potentials defined, 468 list of, A-12–A-14 measurement of, 469 reference electrodes, 538t substitution of, 469 Formation constants conditional, 419 list of, A-10–A-11 Forward biased diodes, 704 Forward scans, 636 Fourier transform infrared (FTIR) instruments advantages of, 714 benchtop, 714 defined, 714 spectrometers, 749 workings of, 715–719 Fourier transform spectrometers, 714, 749–750 Fractional exponents, A-15 Fractograms, 953 Frequency distribution, 96t Fronting, chromatography, 869 Fructose, molecular model, 831 Fullerenes chromatographic separation of, 929–930 defined, 929 Furnace, atomic spectroscopy, 785 Fused silica capillaries for electrophoresis, 942 open tubular column, 891, 897–898, 938 optical properties, 685 G Galvanic cells See also Electrochemical cells defined, 448 discharging, 455 ionic strength effect on potential of, 479t movement of charge in, 452 at open circuit, 447 Galvanostat, 599 Gas chromatography advances in, 907–908 applications, 901–908 basis, 887–888 block diagram, 888 capillary columns, 897, 898 carrier gas system, 888–889 chromatographic detectors, 892–897 column use, 861 defined, 887 in drug metabolite identification in blood, 903–905 ethanol determination in beverages, 1048–1049 high-speed, 907 HPLC comparison, 932t instruments for, 888–897 internal method, 905–906s liquid stationary phases, 899–901 miniaturized systems, 907–908 multidimensional, 908 qualitative analysis, 902 quantitative analysis, 905–906 retention factors, 868 sample injection system, 889–890 temperature effect on, 891 types of, 887 Gas electrode, 456 Gas lasers, 688 Gas-liquid chromatography, 887 See also Gas chromatography Gas-sensing probes defined, 556 diagram of, 557 mechanism of response, 557–558 membrane composition, 556–557 Gas-solid chromatography, 887, 909 Gaussian curves areas under, 101–103 defined, 95, 96 illustrated, 99 properties of, 99–103 GC/MS (gas chromatography/mass spectrometry), 895 Gel filtration, 928 Gel permeation, 928 General elution problem, 882–883 Glass electrodes acid error, 549 alkaline error, 547–548 asymmetry potential, 547 boundary potential, 545–547 composition and structure, 544–545 diagram, 543 hygroscopic, 545 for measuring pH, 542–549 membrane, 542 membrane potentials, 545 for other cations, 549 pH measurements with, 567–569 potential, 547 reference electrode potential between, 558 selectivity coefficient, 548–549 silicate structure, 544 surfaces, 545 Glassine paper, 22 Glassware types, 35 Globar source, 690 Glow discharge, 786 Glucose molecular model of, 137, 831 structural formula, 137 Glycine, 372 Gooch crucible, 29 Gossett, William, 126, 127–128 Gradient elution, 883, 915 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-11 Gram (g), 306 Gran plot, in locating end point, 343 Grand mean, 142, 145 Graphical kinetic methods, 837 Gratings concave, 693 echellete, 692–693 ghosts, 696 holographic, 695, 696 master, 695 reflection, 695 replica, 692, 695 transmission, 695 Gravimetric analysis applications of, 294–298 chloride determination, 996–998 defined, inorganic precipitating agents, 294–295 methods of, 280–298 nickel determination, 999–1000 organic functional groups, 296–297t organic precipitating agents, 295–296 reducing agents, 295 results calculation, 291–294 spreadsheet, 57–61s thermogravimetric, 291 tin determination, 998–999 volatilization gravimetry, 297–298 Gravimetric factor, 292 Gravimetric titrations advantages of, 315 automation, 315 calculations, 315 defined, 302, 314 history of, 314 monographs, A-3 Gravimetry defined, 280 electrogravimetry, 280 precipitation, 280–291 types of, 280 volatilization, 280, 297–298 Greenhouse effect, 200 Grinding samples, 970–971 Gross errors, 87 Gross samples defined, 156, 158 mass definition, 160 number of particles, 159 size of, 158–161 Ground state, 655, 666 Guard column, HPLC, 918 Guard digits, 118 H Half-cell potentials, 455 Half-reactions, 443 Half-titration points, 334 Half-wave potential, 618, 625 Hardness of water determination, 1014–1015 Heart cutting, 908 Heat lamps, 30 Heated objects, manipulation of, 34 Heating equipment, 30 with small flame, 33 Hematocrit (Hct), 559 Henderson-Hasselbalch equation, 221 Heterogeneity, 160 Heterogeneous material, High-performance liquid chromatography (HPLC) adsorption chromatography, 924–925 affinity chromatography, 931 amperometric thin-layer cell for, 921 analytical columns, 917 applications, 913, 914 chiral chromatography, 931–932 column packings, 918–919 column temperature control, 918 columns for, 917–919 components block diagram, 914 defined, 912–913 detectors, 919–921 gas chromatography comparison, 932t gradient elution, 915 instrumentation, 913–921 ion chromatography, 925–927 isocratic elution, 915 mobile-phase reservoirs, 915–916 partition chromatography, 921–924 performance of detectors, 919t precolumns, 917–918 pumping systems, 916 sample injection systems, 916–917 size-exclusion chromatography, 927–930 solvent treatment systems, 915–916 High-pressure microwave vessels, 980–981 High-speed gas chromatography, 907 Histograms defined, 95 illustrated, 97 Hollow-cathode lamps, 791, 792 Holographic gratings, 695, 696 Home water softeners, 860–861 Homogeneous precipitation defined, 289 methods, 290t solids formed by, 289 HPLC See High-performance liquid chromatography Hydrochloric acid for inorganic samples, 978 solution preparation, 1001–1002 standardization against sodium carbonate, 1004 in titrating bases, 382 Hydrodynamic voltammetry applications of, 626–633 concentration profiles, 619–623 defined, 618 mass-transport process, 619 voltammetric currents, 623–626 Hydrofluoric acid, 979 Hydrogen carbonate indicator transition ranges, 392 titration curve, 392 volume relationship of mixtures, 391t Hydrogen cyanide, 407 Hydrogen electrodes, 536 Hydrogen ion diffusion across boundary, 540 generated at face of platinum anodes, 602 Hydrogen peroxide, 511, 629 Hydrogen sulfide defined, 271 dissociation-constant expressions, 270 Hydrolysis, 289 Hydronium ion concentration of weak acids, 213–217 concentration of weak bases, 217–219 concentrations, 270 concentrations, calculating, 359–360 defined, 199, 201 equilibrium shift, 249 polyprotic acid buffers, 355 structures, 199 Hydrophobia, 550 Hydroxide indicator transition ranges, 392 titration curve, 392 volume relationship of mixtures, 391t Hydroxyl groups, 394–395 8-hydroxyquinoline, 295–296, 528 Hygroscopic solids, 27 Hyphenated methods, 817, 897 Hypothesis testing errors in, 138 experimental mean with known value comparison, 129–133 F test, 138–140 null hypothesis, 129 statistical aids to, 129–140 t test, 132–133 two experimental means comparison, 133–137 type I error, 138 type II error, 138 variances comparison, 138–139 z test, 130–132 I ICP See Inductively coupled plasma Ideal blank, 179 Ignition precipitates, 33 of solids, 28–34 Image intensifier, 705 Immobilized enzyme, 842 Immunoassay determination procedure, 274 equilibria in specific determination of drugs, 272–276 fluorescence, 275 measurement step, 273 as powerful tool, 276 Independent analysis, in detection of systematic errors, 91 Indeterminate errors See Random errors Indicator electrodes crystalline-membrane, 553–554 defined, 536 gas-sensing probes, 556–560 glass, 542–549 ideal, 540 ion-sensitive field effect transistors (ISFETs), 554–556 liquid-membrane, 549–553 membrane, 542 metallic, 540–542 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-12 Index Indicators acid/base, 323–326 for added metal ion, 433 adsorption, 413 for analyte, 433 defined, 303 for EDTA titrations, 430–433 oxidation/reduction, 502–505 solution preparation for neutralization titrations, 1001 titration of strong acid with strong base, 329–330 typical changes, 303–305 weak acid/strong base titrations, 335–336 weak base titration, 338 Inductively coupled plasma (ICP) analyte atomization and ionization, 780 appearance and spectra, 779–780 atomic mass spectrometry, 808–809 defined, 778 illustrated, 778 sample introduction, 779 temperature of, 779 Inflection point, 342 Infrared absorption, 667–668 Infrared absorption spectroscopy characteristic absorption peaks, 753t dispersive instruments, 748–749 Fourier transform spectrometers, 749–750 instruments, 748–750 qualitative, 750–752 quantitative, 752–754 spectra, 747–748 Infrared spectrophotometers dispersive, 713–714 Fourier transform, 714–719 Infrared spectrum, 747–748 Ingamells sampling constant, 160 Inhibitors, 826, 843 Initial rate method, 836 Inner-filter effect, 764 Inorganic complexing agents, 406–413 Inorganic precipitating agents, 294–295t Inorganic species absorption by, 724–725 catalytic methods for, 841t extraction, 855–856 fluorescence methods for, 768t Inorganic substances, determination of, 390–393 Insoluble species formation, 404 Instrumental errors, 87–88 Instrumental indeterminate errors, 736t Instrumental uncertainties, 735–739 Integral methods, 837–840 Intensity, 653 Intercept, standard deviation, 174 Interfaces, 451 Interference filters, 697–698 Interference fringes, 716 Interferences in atomic emission spectroscopy, 788–789 in atomic mass spectroscopy, 810–811 defined, 8, 847 elimination of, 8, 11–12 Interferograms, 717, 749 Interferometers, 699 Internal conversion, 678, 761 Internal standard method defined, 182 error compensation, 182 example, 183–184 illustrated, 183 quantitative gas chromatography, 905–906 reference species, 185 International System of Units (SI), 62–63 International Union of Pure and Applied Chemistry (IUPAC), 452–455, 459–460 Introductory experiment aliquot delivery, 989 analytical balance, 987–988 pipet calibration, 990 quantitative transfers, 988–989 reading buret sections, 990–991 sampling, 991–992 sampling error determination, 993–996 Inverse calibration methods, 180 Inverse master equation approach alpha values for redox species, 497–499 defined, 499–500 titration curve, 500 Iodine applications, 526t arsenic reaction, CP-1, CP-2 defined, 525 ferrocyanide reaction, CP-3 oxidizing properties, 1021 preparation of reagents, 1021 properties of, 525 solution standardization, 525, 1021–1022 standard solutions, 525 titrations with, 1021–1023 Ion chromatography conductivity detector, 925 eluent suppressor column, 925 single-column, 927 suppressor-based, 926 Ion exchange applications, 859–861 defined, 857–858 equilibrium, 858–859 process, 857 resins, 858 Ion meters, 561 Ion-exchange resins applications of, 1046–1048 magnesium determination, 1047–1048 separation of cations, 1046–1047 Ionic strength, 246s activity and, 239 activity coefficients and, 239–240 calculation examples, 238 defined, 237 effect of, 237–238 effect of charge on, 238t Ionization analytes, 780 atomic mass spectrometry, 808t, 809–810 in flames, 784 interferences, 789 suppressants, 789 Ion-pair chromatography, 922 Ion-product constant, 205–207 Ion-sensitive field effect transistors (ISFETs) cross-sectional diagram, 555 defined, 554, 555 for measuring pH, 556 structure and performance, 554–556 symbol circuit, 555 Ions See also specific ions activity coefficients for, 242t separation of, 268–276 IR drop, 579–581 Iron complexes of orthophenanthrolines, 504 determination in ore, 1018–1020 determination in various materials, 967t determination in water, 1039–1040 iodide reaction, CP-12 solutions, 512 titration of, 1019–1020 voltammetric behavior of, 625 Irreversible cells, 449 Irreversible reactions, 624–625 Isocratic elution, 883, 915 Isoelectric focusing, 946 Isoelectric point, 372 Isomation method, 169 Isotachophoresis, 946 i-STAT, 559–560 IUPAC See International Union of Pure and Applied Chemistry, 452–455, 459–460 J Jacquinot’s advantage, 719 Jones reductor, 510t Joule (J), 653 Junction potential, 450 – 451 K Karl Fischer reagent applications, 531 classical chemistry, 529 defined, 529 end-point detection, 531 interfering reactions, 530 properties of, 531 pyridine-free chemistry, 530 reaction stoichiometry, 529–530 water determination with, 529–531 Kilogram (kg), 63 Kinetic methods advantages of, 839 applications of, 840–844 catalyzed, 820, 840–843 curve-fitting, 839–840 defined, 819 determination of components in mixtures, 843–844 differential, 835–837 in enzyme activity determination, 843 fixed-time, 838–839 graphical, 837 integral, 837–840 multicomponent, 844 reaction rate determination, 833–840 reaction rates, 820–833 selectivity in, 819 uncatalyzed, 840, 843 Kinetic polarization, 585–586 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-13 Kirchoff, Gustav Robert, 474 Kjeldahl method absolute error plot, 94 amine nitrogen determination by, 1006–1009 defined, 388 development of, 388 distillation apparatus, 1007 example, 389–390 procedure, 1008–1009 sample decomposition, 389 sample digestion, 1006 Knife edges, analytical balance, 21 L Lab-on-a-chip, 168, 745 Laboratory notebook defined, 45 format, 46 maintaining, 45 page illustration, 47 spreadsheet application, 53–57s Laboratory safety, 46–47 Laboratory sample defined, 156 number of, 163–164 preparation of, 11, 162–163 steps in obtaining, 156 Laboratory ware, cleaning and marking of, 17 Laser ablation, 777 Laser-induced breakdown, 786 Laser defined, 687 schematic, 689 sources of, 687–689 types of, 688 LCL See Lower control limit, 188-189 Le Châtelier’s principle, 203 Lead amperometric titration of, 1037–1038 atomic absorption spectroscopy determination of, 1044 electrogravimetric determination in brass, 1032–1034 Least significant difference (LSD), 146 Least-squares method, 171–178s classical, 180 defined, 172 linear relationship assumption, 172 results interpretation, 176–178 weighted, 173 Leveling solvent, 202 Levels, ANOVA, 140 Levitation, 19 Ligand defined, 400–401 protonating, 404–405 selectivity of, 402 unidentate, 402 Light defined, 651 particle nature of, 653 polychromatic, 672 speed of, 652–653 stray, 673 Limestone composition of, 1017 determination of calcium in, 1016–1018 Limiting current, 584, 618 Limiting law Beer’s law, 669 Debye-Hückel, 243 defined, 236 Limiting value, 236 Line spectrum defined, 677 effect of concentration on, 677 energy level diagram, 676 illustrated, 675 Linear calibration curve, 188 Linear dynamic range, 187–188 Linear flow rate, 873 Linear flow velocity, 866 Linear segment curve, 316 Linear-sweep voltammogram, 618 Liquid stationary phase bonded and cross-linked, 901 common, 900t defined, 899–900 film thickness, 901 polarities, 900 widely used, 900–901 Liquid-junction potential, 450–451 Liquid-membrane electrode characteristics, 552t defined, 549 diagram, 550 easy construction of, 552–553 glass electrode comparison, 550 photograph, 551 for potassium ion, 551 sensitivity, 551 Liquid coefficient of expansion, 34 evaporation of, 18 transferring to volumetric flasks, 42 weighing, 27–28 Literature advanced textbooks, A-2 monographs, A-2–A-4 official methods of analysis, A-1–A-2 periodicals, A-4–A-5 review serials, A-2 tabular compilations, A-2 treatises, A-1 Liter (L), 306 Lithium metaborate, 985 Loading error defined, 560 in potential measurements, 560–561 Logarithmic concentration diagram, 377s computation, 375 concentration estimation from, 376 defined, 375 finding pH values with, 376–377 illustrated, 376 system point with, 375 Logarithm buffer capacity as function of, 226 calculation of, A-17–A-18 conclusions, A-18 significant figures in, 117 standard deviation, A-33 standard deviation of, 114–115 Longitudinal diffusion coefficient, 873 Lower control limit (LCL), 188–189 Lowry method, 388 LSD See Least significant difference, 146 M Macro analysis, 154 Macrobalance, 18 Macrocycle, 401 Magnesium determination by direct titration, 1013 ion-exchange chromatography determination of, 1047–1048 Major constituent, 154 Maleic acid alpha values, 373 logarithmic concentration diagram, 376 molecular model, 361 titration curve, 367 Manganese determination in steel, 1040–1041 determination in various materials, 968t Mantissa, of antilogarithm, 115 Masking agent, 182, 414, 434 Mass atomic, 803 defined, 63 equivalent, 393 gross sample, 160 measurement of, 18–25 molar, 50–52, 64, 65 relative, 65 in single-pan balances, 23 standard deviation in, 996t unified atomic mass units, 65 weight relationship, 64 Mass analyzer common, 805t high-resolution, 810 quadrupole, 806 resolution of, 805–806 sector, 806 time-of-flight, 807 Mass chromatogram, 895 Mass number, 803 Mass spectra defined, 802 geological sample, 803 Mass spectrometer components of, 804–805 defined, 804, 895 mass analyzer, 805–807 resolution of, 805–806 transducers for, 807–808 Mass spectroscopy atomic, 808–811 atomic mass, 803 defined, 802 detectors, 895–896 mass-to-charge ratio, 804 molecular, 811–817 principles of, 802–804 tandem, 814–815 transducers for, 807–808 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-14 Index Mass titrations, 315 Mass transfer, 582 Mass-action effect, 203 Mass-balance equation approximations in, 255 defined, 213, 250 proton balance equation, 251 writing, 251, 257, 258, 260–261, 265 Mass-to-charge ratio, 804 Master equation approach, weak acid/strong base titration, 336–337 Master gratings, 695 Matrix defined, 91 effect, 155 modifier, 182 sample, 91 Matrix-matching method, 182, 294s Mean activity coefficient, 242 Mean square value, 143 Mean defined, 84 deviation from, 85 grand, 142, 145 population, 99 sample, 99 standard error of, 105 t test for difference, 134–136 two-sample, 136 Measures of precision coefficient of variation (CV), 109 range, 109 relative standard deviation (RSD), 109 sample standard deviation reliability as, 106–108 variance, 108–109 Mechanical entrapment, 289 Median, 84 Megabore columns, 898 Meinhard nebulizer, 780 Melt, 984 Membrane indicator electrode, 542 Membrane potential, 545 Meniscus, 38 Mercury biological concentration in environment, 798 cathode, 592–593 determining with cold-vapor atomic absorption spectroscopy, 797–798 Metal complex, alpha values for, 403 Metal hydroxide, 257–259 Metal ions added, indicators for, 433 separating as chelates, 855–856 Metal oxide field effect transistor (MOSFET), 554 Metallic indicator electrode See also Indicator electrodes classification of, 540 of the first kind, 540–541 for redox systems, 542 of the second kind, 541 Metals chromium as polished coating, 518 EDTA complex, 417–418 organic reagents for extraction, 414t sampling, 162 Method error analysis of standard samples, 90–91 blank determinations, 91 defined, 87 examples of, 88 independent analysis, 91 variation in sample size, 91 Method of continuous variations, 741–742 Method of standard additions, 185–188, 191 Methods See also specific methods figures of merit for, 186–191 selecting, 4–5, 10 types of, 153–155 Micellar electrokinetic capillary chromatography, 951, 952s Micelles, 950 Michaelis constant, 830t Michaelis-Menten equation, 830 Michaelis-Menten mechanism, 826–829 Michelson interferometer, 715 Micro analysis, 154 Micro total analysis system (mTAS), 168 Microanalytical balance, 18 Microelectrode defined, 615, 646 forms, 646 voltammetry with, 645–647 Microporous membrane, 556–557 Microsoft Excel See also Spreadsheets complex calculations with, 56 equation entry, 50–52 Format Cells window, 51, 58 formula, 50 Goal Seek, 268s layout, 49–50 in molar mass calculation, 50–52 opening window, 49 text and data entry, 50 worksheet documentation, 52 Microwave decomposition See also Decomposition advantages of, 980 applications of, 982 atmospheric-pressure digestion, 981 defined, 979 high-pressure microwave vessel, 980–981 moderate-pressure digestion vessel, 980 Microwave furnaces, 981 Microwave laboratory oven, 30 Microwave oven, 981 Migration, 584 Migration rate distribution constant, 865, 866–867 linear flow velocity, 866 retention factor, 867–868 retention time, 865–866 selectivity factor, 868 of solutes, 865–888 volumetric flow rate, 866 Milligram (mg), 306 Milliliter (mL), 306 Millimole calculating substance amounts in, 65–67 defined, 65 expression of amount in, 306 Miniaturized gas chromatography system, 907–908 Minor constituent, 154–155 Mismatched cells and, 673–674 Mixed-crystal formation, 288, 289 Mixer/mill, 971 ® Mobile-phase flow rate, 872–874 Mobile-phase reservoir, 915–916 Moderate-pressure digestion vessel, 980 Modified electrode, 617 Modulation, 793 Mohr method, 413, 1010 Molar absorptivity, 660, 663s Molar analytical concentration, 68 Molar concentration defined, 67–68, 306 of standard solutions, 307–308 from standardization data, 308–310 Molar equilibrium concentration, 69–70 Molar mass calculation of, 50–52s, 58–59s defined, 64, 65 Molar solubility, 209–211 Molecular absorption, 666–669 Molecular absorption methods cleaning and handling of cells, 1039 directions, 1038 iron determination in natural water, 1039–1040 manganese determination in steel, 1040–1041 spectrophotometric determination of pH, 1041–1042 Molecular absorption spectroscopy absorbing species, 723–725 automated methods, 744–746 infrared, 746–754 qualitative applications, 725–727 quantitative applications, 727–739 ultraviolet and visible, 722–744 Molecular distillation, 852 Molecular fluorescence features, 760 fluorescent species, 763 nonradiative relaxation, 678 quinine determination in beverages, 1043 relaxation processes, 761–762 theory of, 760–763 Molecular formula, 75 Molecular ion, 812 Molecular mass spectrometry See also Mass spectroscopy analysis of mixtures, 816 applications of, 811–812, 815–817 defined, 811 desorption source, 813 gas-phase source, 813 identification of pure compounds, 815–816 instrumentation, 814–815 ion source, 813t quantitative determination, 817 spectra, 812–813 Molecular phosphorescence spectroscopy, 769–770 Mole-ratio method, 742–743 Moles calculating substance amounts in, 65–67 defined, 64 expression in millimoles, 306 Monochromatic radiation, 658 Monochromators, 690–691, 786 MOSFET See Metal oxide field effect transistor, 554 Mother liquor, 286, 997 MSE (mean square due to error), 144 MSF (mean square due to factor levels), 144 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-15 Muffle furnace, 30 Multichannel instrument, 713 Multicomponent kinetic methods, 844 Multidimensional gas chromatography, 908 Multiple additions method, 185–186, 732s Multiple comparison procedure, 140 Multiple linear regression, 181 Multiple-equilibrium problems approximations in solving, 255–256 charge-balance equation, 253–254 computer programs in solving, 256 mass-balance equation, 250–253 solving with systematic method, 250–256 steps for solving, 254–255 Multiplication exponential numbers in, A-16 with scientific notation, A-17 standard deviation, A-31–A-32 Multivariate calibration, 180–181 N National Institute of Standards and Technology (NIST) defined, 16 operational definition of pH, 568–569 Natural broadening, 775 Natural convection, 585 Natural lifetime, 823 Nebulization, 776 Negative bias, 133 Nernst diffusion layer, 622 Nernst equation, 460–462 Nernst glowers, 690 Neutral loss spectrum, 815 Neutralization, 198 Neutralization titration acid content determination, 1005 acid/base ratio determination, 1003–1004 acid/base titration, 323–326 amine nitrogen determination, 1006–1009 applications of, 381–395 atmospheric carbon dioxide effect on, 1001 carbonate-free sodium hydroxide preparation, 1002–1003 composition of solutions during, 341–344 coulometric, 602–603 defined, 322 dilute hydrochloric acid solution preparation, 1001–1002 elemental analysis, 387–390s, 390t end points, CP-9 hydrochloric acid standardization, 1004 indicator solution preparation, 1001 inorganic substance determination, 390–393s organic functional groups determination, 393–395s performance of, 1000 potassium hydrogen phthalate determination, 1005 potentiometric, 570–573 principles of, 322–345 reagents for, 382–387 salts determination, 395s sodium carbonate determination, 1006 sodium hydroxide standardization, 1004–1005 solutions and indicators for, 322–326 standard solutions, 323 Niacin, 86 Nickel, gravimetric determination of, 999–1000 NIST See National Institute of Standards and Technology Nitrate, determination of by acid-base titration, 390 Nitric acid, 978 Nitrite, determination of by acid-base titration, 390 Nitrogen elemental analysis, 388–389 methods for determining, 388 Nitromethane data for decomposition of, 837t plots of kinetics of decomposition of, 838 Noise, 700, 735 Nonessential water, 973 Nonfaradaic current, 635 Nonlinear regression methods, 178 Nonradiative relaxation, 678, 761, 766 Normal error curve, 95, 96 Normal hydrogen electrode (NHE), 456 Normality calculation of, A-22–A-23 defined, A-19, A-22 titration data treatment with, A-23–A-26 volumetric calculations using, A-19–A-26 Normal-phase chromatography, 922 Nucleation, 282 Null comparison, 169 Null hypothesis, 129 Number of degrees of freedom defined, 103 significance of, 104 sum of squares, 143 O Occluded water, 973, 974–975 Occlusion, 289 Ohm’s law, 579 One-tailed tests, 130 One-way ANOVA, 141 Operational amplifier voltage measurement, 562 Optical atomic spectroscopy, 773 Optical instruments components, 683–709 dispersive infrared, 713–714 double-beam, 711–713 infrared spectrophotometer, 713–719 multichannel, 713 optical materials, 684–685 radiant energy detection/measurement, 699–708 sample containers, 708–709 signal processors and readout devices, 708 single-beam, 710–711 spectroscopic sources, 685–690 ultraviolet/visible, 710–713 wavelength selectors, 690–699 Optical materials transmittance ranges, 685 types of, 684 Optical methods, 654 Organic complexing agents, 413–414 Organic compounds, absorption by, 723–724 Organic functional groups analysis of, 296–297t determination of, 393–395 Organic precipitating agent, 295–296 Organic species catalytic methods for, 841–843 fluorescence methods for, 768–769 Organic voltammetric analysis, 643 Outlier approach to, 148 defined, 84, 87, 146 Q test, 147–148 recommendations for treating, 148–149 statistical tests for, 148 Overvoltage defined, 582 with formation of hydrogen and oxygen, 585 lead/acid battery and, 586 Oxalic acid alpha value, 405 molecular structure of, 260 Oxidation effects, 522 Oxidation/reduction indicator choice of, 504 color changes, 502–503 general, 502–504 selected, 503t specific, 504–505 Oxidation/reduction reaction acid/base reaction comparison, 443–445 balancing, 444 defined, 442 in electrochemical cells, 445–446 equivalent weights in, A-20–A-21 Oxidation/reduction titration curve constructing, 488–502 electrode potentials, 489–491 end points, 489 equilibrium concentration and, 492 equivalence-point potential, 493 as independent of reactant concentration, 493 initial potential, 492 inverse master equation approach, 497–500 as symmetric, 494 variable effect on, 501–502 Oxidation/reduction titration applications of, 509–531 coulometric, 603–604t potentiometric, 573 Oxidizing agent cerium(IV), 515–523 defined, 442 permanganate, 515–523 as standard solutions, 515t strong, 515–523 Oxidizing mixture, 979 Oxygen combustion with, 983 sensors, 628 P Packed column electrochromatography, 950 Packed column defined, 890 particle size of supports, 899 solid support materials, 899 Paired t test, 137s defined, 136 example, 137 procedure, 136 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-16 Index Pan arrest, 21 Paper chromatography, 940, 942 Parallax, 38 Parameter, 99 Partial least-squares regression, 181 Partially reversible system, 624 Particle growth, 282 Particle size crystalline precipitates, 286 effect on sampling, 161 experimental control of, 283 methods of improving, 286 precipitates, 281–283 Particulate solid, sampling, 162 Partition chromatography applications, 923–924t bond-phase packings, 921 choice of mobile and stationary phases, 922–923 defined, 921 ion-pair, 922 liquid-bonded-phase, 921 liquid-liquid, 921 normal-phase, 922 reversed-phase, 922 Parts per billion (ppb), 71 Parts per million (ppm), 71, 83 Parts per thousand (ppt), 71 Peptide, 827 Peptization of colloids, 285–286 defined, 285 Percent concentration, 70–71 Percent transmittance, 658 Percentage calculation of, 59s finding with absolute cell references in Excel, 59–61s Perchloric acid, 978 Periodicals, A-4–A-5 Permanganate applications, 521t end-point detection, 516 molecular model of, 515 preparation and stability of standard solutions, 516–519 reaction time dependence, CP-13 standardizing, 519–520 using, 520–522 Personal error, 87, 88–89, 90 Pervaporation, 852 pH buffer maintenance of, 223 buffer solution calculation, 219–222 changes during titration of strong acid with strong base, 328t changes during titration of weak acid with strong base, 333–334t conditional formation constants and, 419 constant, solubility calculations, 260–262 defined, 72 dilution effect, 223 effect on solubility, 260–263 equivalence-point, 333–334 glass electrodes for measuring, 542–549 groundwater, 229 lakes, effect on fish population, 228 logarithmic concentration diagrams, 376–377 NaHA solution calculation, 356–360 operational definition of, 568–569 polyfunctional acid composition as function of, 373–377 polyfunctional systems, 354 spectrophotometric determination of, 1041–1042 titration curves, 317 titration end-point location with, 342–344 unbuffered solutions and, 224 values, finding, 376–377 variable, solubility calculations, 262–263 pH measurement errors affecting, 567–568 operational definition, 568–569 potentiometric, with glass electrode, 567–569 pH meter, 561 Phosphorescence defined, 760, 769 instrumentation, 770 room temperature, 769 spectroscopy, 656 Phosphoroscopes, 770 Phosphors, 769 Phosphorus, determination of, 968t Photoconduction, 700 Photoconductive cells, 704 Photocurrents defined, 702 measuring with operational amplifiers, 708 Photodiode arrays, 704–705 Photoelectrons, 702 Photoemission, 700 Photoluminescence spectroscopy, 656 Photometers defined, 710 filter, 750 with hollow-cathode source, 793 illustrated, 712 Photometric methods, automated, 744–746 Photometric titrations applications of, 740–741 curves, 739 instrumentation, 739–740 Photon detectors charge-transfer devices, 705–707 diode-array, 705 photoconductive cells, 704 photodiodes and arrays, 704–705 Photonmultiplier tubes (PMTs), 702–703 Photons counting, 703 defined, 651, 653 energy of, 653 Physical interferences, 789 Picket fence method, 67 p-ion electrodes, 542 p-Ion meters, 561 Pipets automatic, 36, 37 calibration of, 44, 990 characteristics of, 36 cleaning, 40 defined, 35 directions for using, 39–40 measuring, 36 tolerances, 36 types of, 35 Planar chromatography defined, 862 paper, 940, 942 thin-layer, 940–941 types of, 940 Plasma dc (DCP), 778, 780–781 defined, 778 inductively coupled, 778–780 sources, 777–781 Plate development, 941 Plate height, 870, 880 Platinum black, 456 Plattner diamond mortar, 971 Plus right rule, 454 Pneumatic detectors, 707 Point-of-care testing, 558–560 Polarization concentration, 582–585 current and, 579 defined, 582 effects, 581–586 kinetic, 585–586 Polarograms, 633–634 Polarography, 635s copper and zinc determination in brass, 1036–1037 currents, 633 defined, 610 diffusion current, 634 residual currents, 634–635 voltammetry versus, 610–611 Polychromatic radiation in absorbance measurement, 671 defined, 672 deviation avoidance, 672–673 effect on Beer’s law, 671–673 Polychromators, 690–691, 786 Polyfunctional acids after first equivalence point, 364–365 buffer solutions, 354–356 carbon dioxide/carbonic acid, 352–354 first buffer region, 362 first equivalence point, 363 maleic acid, 367 pH beyond second equivalence point, 366–367 pH calculations, 356–360 pH of, 354 phosphoric acid, 352 prior to first equivalence point, 362–363 prior to second equivalence point, 365–366 role of, 348 second buffer region, 365 second equivalence point, 366 sulfuric acid, 368 system, 352 titration curves, 360–369 triprotic, 367–368 visualization of, 374–375 Polyfunctional bases buffer solutions, 354–356 role of, 348 titration curves, 369–371 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-17 Polypeptides, 827 Polyprotic acids alpha values, 373 buffer solutions involving, 354–356 solution composition as function of pH, 373–377 Pooled standard deviation, 107, 108s Population mean, 99, 100 Population standard deviation, 99, 100 Populations, 98 Position of equilibrium, 202 Postequivalence-point region, 409 Potassium atomic emission spectroscopy determination of, 1045 determination in various materials, 968t Potassium bromate addition reactions, 528 ascorbic acid determination with, 1027–1028 availability, 526 as oxidating agent, 526–528 primary use, 526 solution preparation, 1026 standardization of sodium thiosulfate against, 1027 substitution reactions, 526–528 titrations with, 1026–1028 Potassium dichromate molecular model of, 523 as oxidating agent, 523–526 solution application, 523–524 solution preparation, 523 Potassium hydrogen iodate, 387 Potassium hydrogen phthalate defined, 387 determination in impure sample, 1005 standardization of sodium hydroxide against, 1004–1005 Potassium iodate as primary standard, 513–514 standardization of sodium thiosulfate against, 1023–1024 Potassium permanganate titrations calcium determination, 1016–1018 iron determination, 1018–1020 solution standardization, 1015–1016 Potassium pyrosulfate, 985 Potential, system, 489 Potential of zero charge, 635 Potentiometric end point, 505 Potentiometric measurements cell for, 536 number of, 535 Potentiometric methods defined, 535 direct, 563–564 direct determination of fluoride ion, 1031–1032 equipment for, 535 general principles, 536–537 indicator electrode, 536, 540–560 liquid-junction potential, 539–540 reference electrodes, 536, 537–539 solute species determination in carbonate mixture, 1030 use of, 433, 1028 Potentiometric titrations advantages of, 570 apparatus for, 570 of chloride and iodide in mixture, 1029–1030 data, 569, 570t defined, 569 directions for performing, 1028–1029 dissociation constant determination, 571–573 end-point detection, 570–571 neutralization, 571–573 oxidation/reduction, 573 Potentiometry determination of equilibrium constants, 573–574 direct, 563–569 instruments for measuring cell potential, 560–562 Potentiostatic method apparatus for, 591 applications, 593–594t defined, 588 electrolysis cells, 592 instrumentation, 591–592 mercury cathode, 592–593 Potentiostat, 592, 597, 612 ppm See Parts per million, 71 Precipitant, 850 Precipitate anion, 260 colloidal, 283–286 common-ion effect, 209 creeping, 31 crystalline, 286 drying of, 290–291 filterability of, 281–283 formation mechanism, 282 gelatinous, 29, 31 ignition of, 33, 290–291 low solubility, 283 mass, effect of temperature on, 290 particle size, 281–283 properties of, 281 reaction with excesses of precipitating reagent, 264 solubility of, 264–268 standard electrode potential and, 465–466 transferring to crucible, 32–33 weighting, 30 Precipitating agent inorganic, 294–295t organic, 295–296 Precipitating reagent, 281 Precipitation calculations, 263–264 electrolytic, 851 equivalent weights in, A-21 homogeneous, 289–290 reactions, 400 salt-induced, 851–852 separation by, 848–852 separation of species in trace amounts by, 851 of sulfides, 850t Precipitation gravimetry, 280 Precipitation titrations, 413s argentometric, 408 chloride determination by titration, 1010 chloride determination by weight titration, 1010–1012 concentration effect on curves, 409–410 defined, 407 end points for, 412–413 reaction completeness effect on curves, 410 silver nitrate solution preparation, 1009 titration curve for mixtures of anions, 410–412 titration curve shapes, 408 Precision defined, 84–85 illustrated, 85 Precursor-ion spectrum, 815 Preequivalence-point data, 408 Preparation (sample) crushing and grinding, 970–971 drying, 975 laboratory samples, 970–972 mixing, 972 moisture in samples, 972–975 water in samples, 975 Pressure broadening, 775 Primary absorption, 764 Primary adsorption layer, 284 Primary-standard grade, 16 Primary standard, 305 Primary structure, 827 Principal components regression, 181 Procedures minimizing errors in, 181–186 multiple comparison, 140 Product ions, 815 Product absolute standard deviation of, 111 relative standard deviation (RSD) of, 111 significant figures in, 116 standard deviation of, 111–112 Propagation, of measurement uncertainty, A-29–A-30 Proportional error, 89–90 Protective agent, 789 Proteins defined, 827 salting out, 851 separation, 948t Protonating ligands, 404–405 Proton balance equation, 251–253 in reduction of indicators, 503 Pseudo-equilibrium constant, 830 Pseudo-first-order reaction, 822, 824–826 Pseudostationary phase, 951 Pseudo-zero-order reactions, 830 Pulse voltammetry defined, 639–642 differential-pulse, 639–641 square-wave, 641–642 types of, 639 Pulsed hollow-cathode lamp background correction, 794 Pulsed light source, 685 Pumping, 688 P-value defined, 72 examples, 72–73 Pyrene, molecular model, 768 Pyroelectric detections, 707–708 Pyrolysis, 982 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-18 Index Q Q test critical values, 147t defined, 147 example, 148 illustrated, 147 Quadrupole mass analyzer, 806–807 Qualitative analysis, 2, 153 Qualitative applications (molecular absorption spectroscopy) absorbance/concentration relationship, 729 absorbing species, 728 analysis of mixtures, 733–735 characteristics, 727 instrumental uncertainties and, 735–738 nonabsorbing species, 728 procedural details, 729–735 scope, 728 standard addition method, 729–731 wavelength selection, 729 Qualitative gas chromatography, 902 Qualitative infrared spectrometry, 750–752 Quanta See Photons Quantitative analysis calibration and measurement, defined, 2, 153 flow diagram, interference elimination, measurements, 2–3 method selection, 4–5 methods, results calculation, results evaluation, 8–9 sample acquisition, 5–6 sample processing, 7–8 steps, 4–9 Quantitative fluorescence methods, 766 Quantitative gas chromatography basis, 905 calibration with standards, 905 internal standard method, 905–906 Quantitative infrared spectrometry absorbance measurements, 753 applications, 753–754 ultraviolet/visible spectroscopy versus, 752 vapor analysis, 754t Quantitative transfer, 988–989 Quantum efficiency, 763 Quantum yield, 763, 764 Quaternary structure, 827 Quenching, 766 Quinine fluoresce, 1043 Quotient absolute standard deviation of, 111 relative standard deviation (RSD) of, 111 significant figures in, 116 standard deviation of, 111–112 R Radial viewing geometry, 779 Radiant flux, 687 Radiant power, 653 Radiation absorption of, 658–674 blackbody, 677 buffer, 799 dispersion along focal plane, 694 emission of, 674–679 matter interaction, 654–657 monochromatic, 658 polychromatic, 671–673 properties of, 651–653 stray, 727 transducers, 787 ultraviolet, 668–669 visible, 668–669 Radiation filters absorption, 698 bandwidth for, 697 defined, 696 interference, 697–698 types of, 696 Radioactive decay, 821 Randles-Sevcik equation, 638 Random errors in calibration, 179 in chemical analysis, 93–119 defined, 87 experimental results distribution, 95–98 fundamental sources, 969 nature of, 93–98 sources of, 94–95 statistical treatment of, 98–103 Random samples, 157 Range, as measure of precision, 109 Rate laws See also Reaction rates concentration terms in, 821 defined, 820 for first-order reactions, 821–824 pseudo-first-order reactions, 824–826 for second-order reactions, 824–826 Rate theory of chromatography, 868–869 RDE See Rotating disk electrode, 631–632 Reactant concentration, 501 Reaction completeness effect on redox titration curves, 501 effect on titration curves, 410 Reaction mechanisms, 820 Reaction order, 821 Reaction rates See also Rate laws chemical, 820–833 determination of, 833–840, 840s electrode potentials and, 502 experimental methods, 833–835 kinetic methods, 835–840 units for constants, 821 Readout devices, 708 Reagent blank, 179 Reagents auxiliary oxidizing, 511s auxiliary reducing, 510–511s directions for preparation of, 987 for EDTA titrations, 417 grades, 16 Karl Fischer, 529–531 for metal extraction, 414t for neutralization titrations, 382–387 precipitating, 281 rules for handling, 16–17 selecting and handling, 16–17 selective, 281 special-purpose, 16 Real deviations, 669 Real samples analysis accuracy, 967–969 analysis difficulties, 961–962 analysis objectives, 962 analysis of, 155, 960–969 analytical method selection, 962–967 calcium determination in, 962 composition determination, 961 defined, 961 literature investigation, 964 method accuracy, 963 method selection, 965 number of, 964 problem definition, 962–964 procedure testing, 965–967 standard addition method, 967 Redox equations, 444 Redox equilibrium constants, 482–488s Redox indicators choice of, 504 color changes, 502–503 general, 502–504 selected, 503t specific, 504–505 Redox systems biological, 482 in equilibrium, 484 inert metallic electrodes for, 542 in respiratory chain, 483 Redox titration curves constructing, 488–502 electrode potentials, 489–491 end points, 489 equilibrium concentration and, 492 equivalence-point potential, 493 as independent of reactant concentration, 493 initial potential, 492 inverse master equation approach, 497–500 as symmetric, 494 variable effect on, 501–502 Redox titrations defined, 302 potentiometric, 573 Reducing agents, 295, 442–443 Reductors Jones, 510t uses of, 510t Walden, 510t–511 Reference electrodes See also Potentiometric methods calomel, 537–538 defined, 536, 579, 612 formal potential, 538t glass electrode potential between, 558 silver/silver chloride, 539 Reference method, 388 Reference standards, 16 Reflection grating, 695 Refractory substance, 976 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-19 Regression model, 172 significant, 177 standard deviation, 174 Regression analysis, 172 Relative error defined, 86 differential method, 836 largest, 312 Relative humidity, 973 Relative references, 55s, 60s Relative standard deviation (RSD) antilogarithms, 114 defined, 109 exponential calculations, 112, 113 products and quotients, 111 s symbol, 159 Relative supersaturation, 282 Relaxation processes, 761–762 Releasing agents, 789 Reliability estimation of, 8–9, 12 experimental data, 83 sample standard deviation, 106–108 Replica gratings, 695 Replicates defined, 7, 84 defining, 11 measurement uncertainties and, 83 Reprecipitation, 288, 1017 Representative samples, 11 Residual, 173 Residual currents charging current, 635 defined, 633 illustrated, 635 polarography, 634–635 Resonance fluorescence, 678 Resonance line, 774 Resonance transition, 774 Responses, measurement of, 140 Results ANOVA, 141, 144 calculation of, chemical calculation, 117–119 gravimetric analysis, 291–294 least-squares, 176–178 quality assurance of, 188–191 quantitative analysis, 8–9 random error distribution, 95–98 reliability estimation and, 8–9 reporting, 190–191 spread of, 95 standard deviation of, 110–115 systematic error effect on, 89–90 Retention factor defined, 867–868 effect on column resolution, 878 gas chromatography, 868 variation in selectivity factor and, 880–881 Retention times, 865–866 Reticles, 22 Reversed bias, 705 Reversed-phase chromatography, 922 Reversible cells, 449 Room temperature phosphorescence, 769 Rotating disk electrode (RDE), 631–632 Rotating ring-disk electrode, 632–633 Rotational transitions, 666 Rounding calculations and, 175t data, 117 errors, 118 Rubber policeman, 31 S Safety, laboratory, 46–47 Salt bridges, 446, 538 Salt effect, 239 Salt-induced precipitation, 851–852 Salting in effect, 851 Salts ammonium, 390 defined, 198 determination of, 395 effect of electrolyte concentration on solubility of, 237 mass-balance equations, 251–253 Sample containers, 708–709 Sample injection systems, 889–890, 916–917 Sample matrix, 91 Sample mean, 99 Sample size classification of analyses by, 154 in constant error detection, 91 gross sample, 158–161 liquids and gases, 162 Sample standard deviation, 106s alternative expression for, 104–105 defined, 103 pooling data for improving reliability, 106–108 reliability, 106–108 Sample variance, 103, 108 Samplers, 809 Samples acquisition of, 5–6 analysis of, analytical, 99 automated handling, 164–167 crushing, 970–971 decomposition, 977 defined, 98 dissolution, 11, 977 drying, 975 grinding, 970–971 gross, 156, 158–162 heterogeneous, laboratory, 11, 156, 162–164 liquid, moisture in, 972–975 preparation of, 7, 970–975 processing, 7–8, 11 random, 157 real, 155, 960–969 replicate, 7, 11 representative, 11 solid, solid, mixing, 972 statistical, 99 tools for reducing, 971 types of, 153–155 water in, determining, 975 Sampling defined, 6, 156 error determination, 993–996 homogeneous solutions of liquids and gases, 162 introductory experiment, 991–992 metals and alloys, 162 particulate solids, 162 reliability, steps in process, 157 uncertainties, 157–158 units, 156 Saponification, 394 Saturation method, 182 Scavenger columns, 917 Schöniger combustion apparatus, 983 Scientific notation arithmetic operations with, A-17 exponents in, A-16–A-17 SCOT See Support-coated open tubular, 898 Secondary absorption, 764 Secondary standard solution, 306 Secondary standards, 305 Secondary structure, 827 Second-order reactions, 824–826s Sector analyzers, 806 Sedimentation field-flow fractionation (FFF), 954 Segmented flow analyzers defined, 165 illustrated, 166 Selected-ion monitoring, 895 Selection rules, 676 Selective reagents, 281 Selectivity coefficient, 548–549 of EDTA titrations, 435–436 of electrolytic methods, 586–588 in kinetic methods, 819 ligand, 402 Selectivity factor defined, 868 effect on column resolution, 878 variation in, 881–882 Self-absorption, 788 Self-reversal, 788 Semiconductor lasers, 689 Semimicro analysis, 154 Semimicroanalytical balances, 18 Sensitivity analytical, 187 calibration, 186–187 defined, 186 liquid-membrane electrodes, 551 Sensors defined, 627 enzyme-based, 629–630 oxygen, 628–629 Separations based on control of acidity, 849t by electrolytic precipitation, 851 cation, 1046–1047 chromatographic, 861–883 by control of concentration of precipitating agent, 268–276 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-20 Index Separations (continued ) defined, 847 by distillation, 852 electrophoretic, 945 by extraction, 852–857 feasibility calculation, 268–269 of fullerenes, 929–930 goals of, 848 by inorganic precipitants, 850 by ion exchange, 857–861 methods, 848, 849t monographs, A-4 by organic precipitants, 850 by precipitation, 848–852 preparative, 847 principles of, 848 sample cleanup, 181–182 species in trace amounts, 851 sulfide, 269–271, 850 supercritical fluid, 933–939 Sequential spectrometers, 787 Sequestering agents, 418 Servo system, 19–20 SI See International System of Units, 62–63 Sigmoidal curves, 316 Signal averaging, 752 Signal processors and readout devices, 708 Signal-to-noise ratio, 701 Significance levels, 124 Significant figures convention, 115 defined, 115 in numerical computations, 116–117 in reporting results, 191 rules for determining, 115–116 in titration curve calculations, 331 in volumetric calculations, 309 weak base titration, 337 Silanols, 530 Silicon kilogram, 78 Silicon photodiodes, 704–705 Silver chloride colloidal particle, 284 formation, 996 photodecomposition, 997 reference electrodes, 539 solubility, 413 undissociated, 267 Silver couple, 458 Silver nitrate, 1009 “Silver tree” experiment, 445–446 Silver(I), reduction of, CP-10 Simultaneous spectrometers, 787 Single-beam instruments, 710–711 Single-column ion chromatography, 927 Single-factor ANOVA, 142–145 Single-pan balances air damper, 21 analytical, 19–20 beam arrest, 21 defined, 21 illustrated, 21 masses in, 23 pan arrest, 21 weighing with, 22 Singlet state, 769 Sintered-glass crucibles, 29 Size-exclusion chromatography applications, 928 column packings, 927–928 defined, 927 Skimmers, 809 Slit width, 726 Slope, standard deviation, 174 Slope-ratio method, 743–744 Smith-Hieftje background correction, 794 Sodium atomic emission spectroscopy determination of, 1045 energy level diagram, 676 Sodium acetate, crystallization of, CP-5 Sodium carbonate availability, 382 as flux, 984 standardization of hydrochloric acid against, 1004 titration end points, 383 as washing soda, 382 Sodium chloride, 236–237 Sodium hydrogen carbonate, 370 Sodium hydroxide carbonate-free, 386, 1002–1003 preparation of, 1002–1003 standardization against potassium hydrogen phthalate, 1004–1005 Sodium peroxide, 511 Sodium tetraphenylborate, 296 Sodium thiosulfate defined, 512 preparation of, 1023 primary standards for, 514 solution applications, 514t solution stability, 513 solution standardization, 513–514 standardization against copper, 1024 standardization against potassium bromate, 1027 standardization against potassium iodate, 1023 in strongly acidic medium, 513 titrations with, 1023–1026 Solar spectrum, CP-17 Solid-phase extraction, 856–857 Solid-phase microextraction, 857 Solids filtration and ignition of, 28–34 sampling, 162 weighing, 27 Solid-state lasers, 688 Solubility calculating by systematic method, 256–268 concentration-based, 244 equilibria, 404 metal hydroxides, 257–259 molar, 209–211 pH effect on, 260–263 pH variability calculations, 262–263 precipitates, 264–268 product constants, A-6–A-7 Solubility-product constants common ion effect, 209–211 defined, 208 precipitate in water, 208 using, 207–211 Solute volatilization interferences, 789 Solutes effect on precipitation calculations, 263–264 migration rates, 865–888 Solution-diluent volume ratios, 72 Solutions acid/base titrations, 322–326 blank, 91 buffer, 219–231 chemical composition of, 197–202 composition during acid/base titrations, 341–344 concentration of, 67–73 density of, 73–75 of electrolytes, 197–198 iron(II), 512 preparation of, 7–8 rules for handling, 16–17 specific gravity of, 73–75 standard, 305–306 stirred, electrode profile, 621–623 turbidity of, 740 unstirred, electrode profile, 619–621 Solvent blank, 179 Solvent programming, 883 Solvents amphiprotic, 200 differentiating, 201–202 dissolution conditions, eluent, 862 leveling, 202 for organic voltammetry, 643 protein donors, 198–199 treatment systems, 915–916 ultraviolet/visible spectroscopy, 726t Solvers, 256 Sorbed water, 973, 974 Sparging, 386, 915 Spark source atomic mass spectrometry (SSMS), 809 Special-purpose reagent chemicals, 16 Specific gravity of concentrated acids/bases, 74t defined, 73 of solutions, 73–75 Specific surface area of colloids, 287–288 defined, 287 Spectra absorption, 664–669 atomic, 774–776, 784 band, 677 continuum, 677 continuum light source, 718 defined, 655 electromagnetic, CP-21 excitation spectrum, 762 infrared absorption, 747–748 line, 674–676, 677 mass, 802 molecular mass, 812–813 neutral loss, 815 precursor-ion, 815 producing with FTIR spectrometers, 751–752 product ion, 815 solar, CP-17 three-dimensional MS/MS, 815 visible, 665 white light, CP-16 Spectral bandpass, 691 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-21 Spectral interferences, 789 Spectrofluorometers, 765 Spectrographs, 690, 786 Spectrometers defined, 710 direct reading, 787 Fourier transform, 714, 749–750 ICP atomic emission, 786 magnetic sector, 806 mass, 804–808, 895 multichannel, 713 sequential, 787 simultaneous, 787 tandem mass, 815 Spectrometric methods, monographs, A-3 Spectrophotometers, 793–794 defined, 710 double-beam schematic, 793 illustrated, 711 infrared, 713–719 linear CCD arrays for, CP-14 radiation bands, 672 Spectrophotometric methods automated, 744–746 defined, 433 determination of pH, 1041–1042 measurements, 739s titrations, 741s Spectroscopic analysis, Spectroscopic measurements, 655–657 Spectroscopy absorption, 656, 662 atomic, 773–799 chemiluminescence, 655 continuum sources, 686t defined, 646 discovery of elements and, 657 emission, 655 fluorescence, 656 infrared absorption, 746–754 instruments for, 683–719 introduction to, 650–679 mass, 802–817 molecular absorption, 722–754 molecular fluorescence, 760–770 molecular phosphorescence, 769–770 optical, 683 phosphorescence, 656 photoluminescence, 656 Spontaneous cell reaction, 448 Spread defined, 95 as measure of precision, 109 Spreadsheet exercises alpha values and conditional formation constants, 406s alpha values for redox species, 502s amperometric titration, 633s capillary electrophoresis, 949s chemical equilibrium, 219s chromatography, 883s complex calculation, 404s complexometric titration, 407s confidence intervals, 126s continuous variations, 744s controlled-potential coulometry, 598s coulometric titration curve, 605s EDTA titration curves, 425s, 426s electrode potentials, 469s, 480s enzyme catalysis, 833s equilibrium constants from standard potentials, 488s Excel Goal Seek, 268s F test, 140s first-/second-order reactions, 826s gas chromatography internal method, 905–906s ionic strength, 246s least-squares analysis, 178s logarithmic concentration diagrams, 377s matrix inversion method, 294s mean and standard deviation, 106s micellar electrokinetic capillary chromatography, 952s molar absorptivity, 663s multiple standard additions method, 732s multiple standard additions procedure, 186s overlapped chromatogram, 932s paired t test, 137s polarography, 635s pooled standard deviation, 108s precipitation titration, 413s reaction rate determination, 840s sample standard deviation, 106s spectrophotometric measurements, 739s spectrophotometric titrations, 741s stray light, 674s strong acid/base titrations, 331s t test, 136s titration curves, 318s titration curves of polyfunctional acids, 369s titration curves of polyfunctional bases, 370s titration end point, 344s titration of amphiprotic species, 372s weak acid/strong base titrations, 337s Spreadsheets See also Microsoft Excel in analytical chemistry, 48–61 cells, filling with fill handle, 55–56 data entry for unknown samples, 995 decomposition of variances, 995 entering numbers in, 54 formulas, 50 for recordkeeping and calculations, 49–52 relative references, 55s Sputtering, 792 Square-wave voltammetry defined, 641 excitation signal generation, 641 instruments for, 642 SRMs See Standard reference materials, 90, 966 SST See Total sum of squares, 143 Standard addition method, 566–567 defined, 566 molecular absorption spectroscopy, 729–731 real samples, 967 Standard cell potential, 452 Standard deviation addition, A-30–A-31 of antilogarithms, 114–115, A-33 of calculated results, 110–115 calibration curve, 174 of computed results, A-30–A-33 difference between means, 134 division, A-31–A-32 exponential calculations, 112–113, A-32–A-33 intercept, 174 of logarithm, 114–115, A-33 in mass, 996t multiplication, A-31–A-32 pooled, 107 population, 99, 100–101 of product and quotient, 111–112 regression, 174 relative (RSD), 109 rounding and, 105 sample, 103–106 silica results, 969t slope, 174 subtraction, A-30–A-31 of sum and difference, 110–111 in volume, 996t Standard electrode potential applications of, 473–505 calculating equilibrium constants from, 487 calculating potentials of electrochemical cells, 473–480s calculating redox equilibrium constants, 482–488s calculating redox titration curves, 488–502s characteristics, 462–463 constructing redox titration curves, 488–502s data availability, 463 data tabulation, 463, 464t defined, 457, 460, 462 experimental determination of, 480–482s lack of dependence on number of moles of reactants and products, 463 limitations to use of, 467–469 list of, A-12–A-14 measurement of, 459, 466 oxidation/reduction indicators, 502–505s relative force measurement, 462 as relative quantity, 462 systems involving precipitates or complex ions, 465–466 Standard error of the estimate, 174 Standard error of the mean, 105 Standard hydrogen electrode (SHE), 456 Standard oxidizing agents applying, 515–531s potassium bromate, 526–528 potassium dichromate, 523–526 Standard reducing agents, applying, 511–514s Standard reference materials (SRMs), 90, 966 Standard sample, 966 Standard solution acid/base titrations, 323 acids, 382–385 bases, 385–387 compounds recommended for preparation of, A-27–A-28 methods for, 305–306 molar concentration of, 307–308 oxidants as, 515t strong acids/bases, 322 strong bases, 387 Standard state, 452 Standardization of acids, 382–385 of bases, 387 defined, 306 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-22 Index Starch, decomposition, 513 Starch/iodine solution, 504 Statistical control, 189 Statistical samples, 99 Statistics ANOVA, 140–146 confidence intervals, 123, 124 defined, 99 gross error testing, 140–146 hypothesis testing, 129–140 treatment of data with, 123–149 Steady-state approximation, 829 Stepwise formation constant, 205t Stibnite, 1022–1023 Stimulated emission, 687 Stoichiometric ratio, 311 Stoichiometry calculations, 76–78 of chemical reactions, 75–78 defined, 75 flow diagram for calculations, 76 Stokes shift, 679 Stokes-shifted fluorescence, 762 Stopcocks lubricating, 40–41 manipulating, 42 Stopped-flow mixing, 833–834 Stray light, 673, 674s Stripping methods anodic, 643–644 cathodic, 643–644 electrodeposition step, 644–645 voltammetric completion of analysis, 645 Strong acid pH changes during titration of, 328 titrating strong base with, 330–331 titrating with strong base, 326–330 titration curves for, 332 titration of, 326–331 Strong base pH changes during titration of, 328 standard solutions of, 387 titrating strong acid with, 326–330 titrating with strong acid, 330–331 titration curves for, 330 titration of, 326–331 Strong electrolyte, 197 Strong/weak acid, 351 Structural formula, 76 Student’s t, 126, 128 Substances, determining, Substrates, 826, 831, 842t Subtraction scientific notation, A-17 standard deviation in, A-30–A-31 Sucrose, molecular model, 841 Sulfanilamide, molecular model, 527–528 Sulfide concentration as function of pH, 270 determination by gravimetric volatilization, 298 precipitation of, 850t separations, 269–271, 850 Sulfite, 298 Sulfonic acids, 393 Sulfur, elemental analysis, 390 Sulfur dioxide, 390 Sulfuric acid decomposition with, 978 dissociation of, 368–369 titration curve, 368 Sum significant figures in, 116 of squares, 142–143 standard deviation of, 110–111 variance of, 110 Supercritical fluid chromatography (SFC) applications, 939 for chiral separations, 939 column methods versus, 938–939 columns, 937–938 defined, 935 detectors, 938 effects of pressure, 937 instrumentation, 937–938 mobile phases, 938 operating variables, 937–938 Supercritical fluid critical temperature, 936 defined, 936 properties comparison, 936t properties of, 936–937 Support-coated open tubular (SCOT), 898 Supporting electrolytes, 612 Suppressor-based ion chromatography, 926 Surface adsorption See also Coprecipitation defined, 286 minimizing adsorbed impurities of colloids, 287–288 reprecipitation, 288 Switching potential, 636 System points, 375 Systematic error in calibration, 179 constant, 89 defined, 87–91 detection of, 90–91 effect on results, 89–90 fundamental sources, 969 instrumental, 87–88 method, 87, 88, 90–91 personal, 87, 88–89, 90 proportional, 89–90 sources of, 87–89 types of, 87 Systematic method multiple-equilibrium problem solutions with, 250–256 solubilities calculations with, 256–268 T t statistic critical value comparison, 135 defined, 126 values of, 127t t test, 136s defined, 132 for differences of means, 134–136 example, 133 illustrated, 133 paired, 136–137 procedure, 132 Tailing, chromatography, 869 Tandem mass spectrometry, 814 Taring control, 20 Temperature effect on weighing data, 24 programming, 883, 891 in volumetric measurements, 35 Tertiary structure, 827 Thermal conductivity detector (TCD), 893–894 Thermal detectors, 707–708 Thermal field-flow fractionation (FFF), 955 Thermobalance, 291 Thermogram, 291 Thermogravimetric analysis, 291 Thermopile, 707 Thin-layer chromatography (TLC) analytes location on plate, 941 defined, 940 plate development, 941 plate preparation, 940–941 principles of, 940–941 sample application, 941 Thiosulfate ion defined, 512 iodine, end points, 512–513 molecular model of, 512 quantitative conversion of, 512 Three-dimensional MS/MS spectrum, 815 Three-electrode cells, 580 Time dependence, CP-13 Time-of-flight mass analyzers, 807 Tin, gravimetric determination of, 998–999 TISAB See Total ionic strength adjustment buffer, 566 Titration curve, 318s acetic acid with sodium hydroxide, 335 amperometric, 630 for amphiprotic species, 371–372 calculated with inverse master equation approach, 500 calculating, 317–318 charge-balance equation in constructing, 328–329 complexometric, 406 defined, 315 diprotic acid, 360 EDTA, 422–427 effect of concentration on, 409–410 effect of reaction completeness on, 410 experimental, 326 hypothetical, 326 illustrated, 316, 317 inflection point, 342 linear segment, 317 mixtures of anions, 410–412 photometric, 739 polyfunctional acids, 360–369s polyfunctional bases, 369–371, 370s precipitation titrations, 408–410 redox, 488–502 shapes of, 408 sigmoidal, 316 significant figures, 331 strong acid, 332 strong base, 330 strong/weak acid, 351 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Index I-23 types of, 316–317 weak acid, 332 weak base, 337–341 Titration data molar concentrations from, 308–310 quantity of analyte from, 310–314 working with, 308–314 Titration aminocarboxylic acid, 414–437 amperometric, 302, 630–631 argentometric, 408 back-titration, 303 complexation, 406–407 complex-formation, 1012–1015 complexometric, 401 coulometric, 302, 599–606, 1034–1036 direct, 433 end point, 303, 304, 342 equivalence point, 303 gravimetric, 302, 314–315 indicators, 303–305 inorganic complex-forming, 407t with iodine, 1021–1023 mass, 315 neutralization, 322–345, 1000–1009 with potassium bromate, 1026–1028 with potassium permanganate, 1015–1020 potentiometric, 569–573 precipitation, 407–413, 1009–1112 primary standards, 305 redox, 302 secondary standard solution, 306 spectrophotometric, 302 stopcock manipulation, 42 typical setup, 304 volumetric, 302, 303–305, 306–314 Titrator automatic, 570 potentiometric, 575 TLC See Thin-layer chromatography, 940–941 Top-loading balance, 25 Total ionic strength adjustment buffer (TISAB), 566 Total sum of squares (SST), 143 Total-ion chromatogram, 895 Totally reversible system, 624 Trace constituents, 155 Transducers defined, 699 for mass spectrometry, 807–808 properties of, 699–700 radiation, 787 types of, 700–702 Transformations, to linearize functions, 178t Transformed variables, 178 Transmission gratings, 695 Transmittance conversion spreadsheet relating, 659 defined, 658 measurement errors, 736t measurement of, 659–660 percent, 658 ranges for optical materials, 685 Trichloroacetic acid, molecular model, 70 Triple-beam balance, 25 Triplet state, 769 TRIS defined, 383 molecular structure of, 384 Tswett, Mikhail, 864 Turbidimetry, 740 Two-sample t test, 136 Two-tailed tests, 130 Two-way ANOVA, 141 Tyndall effect defined, 282 illustrated, CP-6 U UCL See Upper control limit, 188–189 Ultramicro analysis, 154 Ultramicroelectrode, 615 Ultratrace constituent, 155 Uncatalyzed reaction, 843 Uncertainty calibration curve, 180 concentration, 735 independent, A-30 measurement, propagation of, A-29–A-30 possible combinations of, 94t random, A-30 sampling, 157–158 spectrophotometric concentration measurements, 736 Uncontrolled-potential electrogravimetry applications, 589–590, 591t defined, 588 electrolysis cells, 589 instrumentation, 588–589 physical properties of electrolytic precipitates, 589 Unidentate, 401 Unified atomic mass unit, 803 Units of measurement kilogram, 63 millimole, 65 mole, 64–65 prefixes, 63 SI units, 62–63 Universe, 98 Upper control limit (UCL), 188–189 Urea enzymatic determination of, 842 molecular model of, 842 Uric acid, molecular model, 841 V Vacuum distillation, 852 Validation, 190 Variable defined, 99 effect on redox titration curves, 501–502 transformed, 178 Variance ratio, 142 Variance comparison of, 138–140 defined, 100, 108 of difference, 110 sample, 108 of sum, 110 Vibrational deactivation, 678 Vibrational relaxation, 761 Vibrational transition, 666 Vitamin E, 522 Volatilization gravimetry application of, 297–298 defined, 280 determination apparatus, 298 Volhard method, 412–413 Volta, Alessandro, 449 Voltage defined, 446 experimental curve, 582 in irreversible reactions, 624–625 time excitation signals versus, 611 Voltammetric and amperometric sensors defined, 627 enzyme-based, 629–630 oxygen, 628–629 Voltammetric current, 623–626 Voltammetric detector, 626–627 Voltammetric instrument based on operational amplifiers, 613–615 current-to-voltage converter, 614 modified electrodes, 617 potentiostat, 612, 613 signal source, 613 voltammograms, 617–618 working electrodes, 615–617 Voltammetric waves, 618 Voltammetry amperometric titration of lead, 1037–1038 applications of, 642–643 copper and zinc determination in brass, 1036–1037 cyclic, 635–639 defined, 610 differential-pulse, 639–641 excitation signals, 611–612 hydrodynamic, 618–633 inorganic analysis, 642 manual potentiostat for, 612 with microelectrodes, 645–647 organic analysis, 643 polarography versus, 610–611 pulse, 639–642 square-wave, 639–641 stripping method, 643–645 use of, 610 Voltammogram anodic and mixed anodic/cathodic, 625 defined, 617 differential-pulse anodic stripping, 646 differential-pulse polarography experiment, 640 linear-sweep, 618 for mixtures of reactants, 625 for reduction of oxygen, 626 Volume measurement aliquot, 40 apparatus, 35–38 standard deviation in, 996t temperature effects on, 34–35 units of, 34 Volume percent, 71 Volume ratios, solution-diluent, 72 Volumetric analysis, Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it I-24 Index Volumetric calculations, 308–314 molar concentration of standard solutions, 307 with normality and equivalent weight, A-19–A-26 relationships, 306 significant figures in, 309 titration data and, 308–314 Volumetric equipment calibration of, 43–45 cleaning, 38 types of, 35 using, 38 Volumetric flask calibration of, 45 defined, 37 diluting to the mark, 43 direct weighing into, 42 directions for using, 42–43 illustrated, 38 quantitative transfer to, 42 tolerances, 37 Volumetric flow rate, 866, 873 Volumetric titration defined, 302 performance of, 303 standard solutions, 303, 305–306 terminology, 303–305 W Walden reductor, 510t–511 Wall-coated open tubular (WCOT), 898 Washing by decantation, 31 precipitates, 30–31 Water as acid or base, 200 adsorbed, 973, 974 calcium determination in, 281 in carbonate-free solutions, 386 determining in samples, 975 determining with Karl Fischer reagent, 529–531 in equilibrium with atmospheric constituents, 386 essential, 972–974 ion-product constant for, 205 nonessential, 973 occluded, 973, 974–975 as protein acceptor, 199 purification of, 987 in solids, 972–973 sorbed, 973, 974 Water hardness calcium, 436 determination, 436–437, 1014–1015 test kits for, 436 Wavelength defined, 652 units, 652t Wavelength selector See also Optical instruments grating, 692–696 monochromator, 690–691 polychromator, 690–691 radiation filter, 696–699 Wavenumber, 652, 653 Wave frequency, 652 period, 652 properties of, 651–653 velocity, 652 WCOT See Wall-coated open tubular, 898 Weak acid defined, 201 dissociation constants of, 334–335 hydronium ion concentration of solutions of, 213–217 titration curves for, 332–337 weak bases and, 371 Weak acid/strong base titration, 337s effect of concentration, 335 effect of reaction completeness, 335 indicator selection, 335–336 master equation approach, 336–337 Weak base titration base strength effect, 339 challenge, 338 indicator selection, 338 significant figures, 337 Weak base dissociation constants of, 334–335 hydronium ion concentration of solutions of, 217–219 titration curves for, 337–341 weak acids and, 371 Weak electrolyte, 197 Web Works acid rain, 232 acid/base behavior, 345 AIDS and HIV, 276 anodic stripping voltammetry (ASV), 647 Avogadro’s number, 78 CE-MS applications, 957 chemical properties and toxicity, 1050 chromatography, 883 coulometer, 605 Debye and Hückel theory of electrolytic solutions, 247 digital object identifier (DOI), 298 distance-of-flight (DOF) mass spectrometry, 817 EDTA solutions, 437 Electrochemical Society (ECS), 505 Excel file formats, 60 fluorescence measurement correction, 770 fuel cell technology, 469 gas chromatographic instrument, 909 gas chromatography, 909 ICP matrix effects, 799 IR spectrum, 754 Lake Champlain Basin Agricultural Watersheds Project, 395 LC-GC magazine, 933 method of standard additions, 191 molar absorption coefficient, 679 NIST statistical data, 119 potassium dichromate, 531 potentiometric titrators, 575 spectrophotometric analyzer and electrochemical analyzer comparison, 844 statistics for writers, 91 Statistics Textbook, 149 titrations, 318 Virtual Titrator Java applet, 377 Weighing defined, 64 by difference, 27, CP-19, CP-20 equipment and manipulations with, 25–28 errors, 22–25 hygroscopic solids, 27 liquids, 27–28 temperature effects on, 24 into volumetric flasks, 42 Weighing bottle defined, 25–26 illustrated, 26 manipulating, 27 Weight concentration, 315 crucible, 63–64 defined, 63, 64 mass relationship, 64 percent, 71 Weight titration chloride determination by, 1010–1012 directions for performing, 1011 Weighted least-squares analysis, 172, 173 Weight/volume percent, 71 Wet ashing, 18 Wet washing, 978 Winkler method, 391 Working curve, 171 Working electrode defined, 579, 588, 612 illustrated, 616 microelectrode, 615 potential ranges of, 616 ultramicroelectrode, 615 in voltammetry, 615 Worksheets column width, changing, 53–54 documenting, 52, 56–57 entering numbers in, 54 entering text and data in, 50 formulas in, 50, 52 text entry, 53 Z z test defined, 134 examples of, 131–132 one-tailed, 130 procedure, 130 rejection regions, 130, 131 two-tailed, 130 Zeeman effect background correction, 794 Zinc, polarographic determination in brass, 1036–1037 Zwitterion defined, 200, 372 molecular structure of, 372 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it ... Br2(aq) 2e2 2Br2 Br2(l ) 2e2 2Br2 Ag1 e2 Ag(s) Fe31 e2 Fe21 I 321 2e2 3I2 Cu21 2e2 Cu(s) UO 221 4H1 2e2 U41 2H2O Hg2Cl2(s) 2e2 2Hg(l ) 2Cl2 AgCl(s) e2 Ag(s)1Cl2 Ag(S2O3 )23 2 e2 Ag(s) 2S2O 322 2H1 2e2... Precipitates or Complex Ions In Table 18-1, we find several entries involving Ag(I) including Ag1 e2 Ag(s) EAg /Ag 10.799 V AgCl(s) e2 Ag(s) Cl2 EAgCl/Ag 10 .22 2 V Ag(S2O3 )23 2 e2 Ag(s) 2S2O 322 32 EAg(S... * (a) MnO 42 VO21 S Mn21 V(OH)41 (b) I2 H2S(g) S I21S(s) *(c) Cr2O 722 U41 S Cr31 UO 221 (d) Cl2 MnO2(s) S Cl2(g) Mn21 *(e) IO 32 I2 S I2(aq) (f ) IO 32 I2 Cl2 S ICl 22 *(g) HPO 322 1 MnO 42 1OH2
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