Chapter 12 Solutions 2011, NKMB Co., Ltd. Chemistry, Julia Burdge, 2 st Ed. McGraw Hill. Mr. Truong Minh Chien ; losedtales@yahoo.com http://tailieu.vn/losedtales http://mba-programming.blogspot.com 2 Solution • homogeneous mixtures  composition may vary from one sample to another  appears to be one substance, though really contains multiple materials • most homogeneous materials we encounter are actually solutions  e.g., air and sea water • nature has a tendency toward spontaneous mixing  generally, uniform mixing is more energetically favorable Chemistry, Julia Burdge, 2 nd e., McGraw Hill. Solutions animation 3 Chemistry, Julia Burdge, 2 nd e., McGraw Hill. 4 Solutions • solute is the dissolved substance  seems to “disappear”  “takes on the state” of the solvent • solvent is the substance solute dissolves in  does not appear to change state • when both solute and solvent have the same state, the solvent is the component present in the highest percentage • solutions in which the solvent is water are called aqueous solutions Chemistry, Julia Burdge, 2 nd e., McGraw Hill. 5 Seawater • drinking seawater will dehydrate you and give you diarrhea • the cell wall acts as a barrier to solute moving • the only way for the seawater and the cell solution to have uniform mixing is for water to flow out of the cells of your intestine and into your digestive tract Chemistry, Julia Burdge, 2 nd e., McGraw Hill. 6 Common Types of Solution Solution Phase Solute Phase Solvent Phase Example gaseous solutions gas gas air (mostly N 2 & O 2 ) liquid solutions gas liquid solid liquid liquid liquid soda (CO 2 in H 2 O) vodka (C 2 H 5 OH in H 2 O) seawater (NaCl in H 2 O) solid solutions solid solid brass (Zn in Cu) • solutions that contain Hg and some other metal are called amalgams • solutions that contain metal solutes and a metal solvent are called alloys Chemistry, Julia Burdge, 2 nd e., McGraw Hill. 7 Brass Type Color % Cu % Zn Density g/cm 3 MP °C Tensile Strength psi Uses Gilding redish 95 5 8.86 1066 50K pre-83 pennies, munitions, plaques Commercial bronze 90 10 8.80 1043 61K door knobs, grillwork Jewelry bronze 87.5 12.5 8.78 1035 66K costume jewelry Red golden 85 15 8.75 1027 70K electrical sockets, fasteners & eyelets Low deep yellow 80 20 8.67 999 74K musical instruments, clock dials Cartridge yellow 70 30 8.47 954 76K car radiator cores Common yellow 67 33 8.42 940 70K lamp fixtures, bead chain Muntz metal yellow 60 40 8.39 904 70K nuts & bolts, brazing rods Tro, Chemistry: A Molecular Approach 8 Solubility • when one substance (solute) dissolves in another (solvent) it is said to be soluble  salt is soluble in water  bromine is soluble in methylene chloride • when one substance does not dissolve in another it is said to be insoluble  oil is insoluble in water • the solubility of one substance in another depends on two factors – nature’s tendency towards mixing, and the types of intermolecular attractive forces Tro, Chemistry: A Molecular Approach 9 Spontaneous Mixing Tro, Chemistry: A Molecular Approach 10 Solubility • there is usually a limit to the solubility of one substance in another  gases are always soluble in each other  two liquids that are mutually soluble are said to be miscible  alcohol and water are miscible  oil and water are immiscible • the maximum amount of solute that can be dissolved in a given amount of solvent is called the solubility • the solubility of one substance in another varies with temperature and pressure [...]... in the formation of most solutions also • involve differences in attractive forces between particles must overcome solute-solute attractive forces  endothermic • must overcome some of the solvent-solvent attractive forces  endothermic • at least some of the energy to do this comes from making new solute-solvent attractions  exothermic Tro, Chemistry: A Molecular Approach 12 Intermolecular Attractions... C-Cl, but symmetrical Tro, Chemistry: A Molecular Approach 18 Example 12. 1a − predict whether the following vitamin is soluble in fat or water OH The 4 OH groups make the molecule highly polar and it will also Hbond to water Vitamin C is water soluble OH H2C C H H C O C C HO O C OH Vitamin C Tro, Chemistry: A Molecular Approach 19 Example 12. 1b − predict whether the following vitamin is soluble in fat or... You Make a Solvent Hold More Solute Than It Is Able To? • solutions can be made saturated at non-room conditions • • – then allowed to come to room conditions slowly for some solutes, instead of coming out of solution when the conditions change, they get stuck in-between the solvent molecules and the solution becomes supersaturated supersaturated solutions are unstable and lose all the solute above saturation... solvent, the overall process will be exothermic endothermic Tro, Chemistry: A Molecular Approach 23 Energy of Solution animation Tro, Chemistry: A Molecular Approach 24 Heats of Hydration • for aqueous ionic solutions, the energy added to overcome the attractions between water molecules and the energy released in forming attractions between the water molecules and ions is combined into a term called the heat... 42.6 45.5 48.3 51.1 54 56.7 35.7 35.8 36 36.3 36.6 37 37.3 37.8 38.4 39 39.8 29.4 33.3 37.2 41.1 45.8 50.4 55.2 60.2 65.6 71.3 77.3 35.3 354 34.2 33.5 32.7 32.5 31.9 29.9 0.185 0.176 0.165 0.153 0.141 0 .128 0.116 0.106 0.094 0.085 0.077 984 222 844 -1720 -927 Tro, Chemistry: A Molecular Approach 30.7 21.4 9.84 7.24 5.63 13.9 21.2 31.6 45.3 61.3 3.87 106 167 203 245 35 Tro, Chemistry: A Molecular Approach . Chapter 12 Solutions 2011, NKMB Co., Ltd. Chemistry, Julia Burdge, 2 st Ed. McGraw. (NaCl in H 2 O) solid solutions solid solid brass (Zn in Cu) • solutions that contain Hg and some other metal are called amalgams • solutions that contain