meyer (akm995) – Homework 2 – fakhreddine – (51650) 1 This print-out should have 31 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 1.0points The mole fraction of a certain nonelectrolyte compound in a solution containing only that substance and water is 0.100. The molecular weight of water is 18.0 g/mol. What addi- tional information is needed to determine the molality of the solution? 1. The molecular weight of the compound. 2. No additional information; the molal- ity can be calculated from the information given. 3. The mole fraction of water in the solu- tion. 4. The density of the solute. 5. The density of the solution. 002 1.0points What additional information, if any, would enable you to calculate the molality of a 7.35 molar solution of a nonelectrolyte solid dis- solved in water? 1. Only the density of the solution would be needed. 2. Only the molecular weight of the solute would be needed. 3. Both the density of the solution and the molecular weight of the solute would be needed. 4. None is needed. 5. Only the density of water would be needed. 003 1.0points A solution is 40.0% silver nitrate (AgNO 3 ) by mass. The density of this solution is 1.48 grams/mL. The formula weight of AgNO 3 is 170 grams/mol. Calculate the molality of AgNO 3 in this solution. Answer in units of m . 004 1.0points Water causes many electrolytes to dissociate 1. because the dispersion forces between ion and solvent are strong. 2. because it undergoes hydrogen bonding to large halide ions. 3. because water molecules are dipoles and the dipoles orient in an energetically favorable manner to solvate the ions. 4. because of repulsive interactions between ions in the crystalline state. 005 1.0points For which of the following ions would the hydration process give off the least heat? 1. Al 3+ 2. K + 3. Ba +2 4. Li + 5. Mg +2 006 1.0points Consider two solutes with the same lattice energy in kJ/mol; however, the particles of solute A are strongly solvated by water, while those of solute B are only weakly solvated. Which of the two dissolution processes is more exothermic, on a kJ/mol basis? 1. It depends on the molecular weights of the solutes. 2. Cannot be answered without knowing the identities of the solutes.
meyer (akm995) – Homework 2 – fakhreddine – (51650) 2 3. Both processes are equally exothermic. 4. dissolving B in water 5. dissolving A in water 007 1.0points Consider a series of chloride salts (MCl 2 ). As the charge-to-size ratio of M 2+ (decreases, increases) the hydration energy of M 2+ (de- creases, increases, does not change) in magni- tude and the crystal lattice energy of MCl 2 (decreases, increases, may increase or de- crease) in magnitude.
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- Mole, Vapor pressure, Meyer