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Unformatted text preview: Version 383 Exam 2 Sutcliffe (52410) 1 This print-out should have 28 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Which of Acid X [HX] = 10 3 M K a = 1 . 32 10 6 Acid Y [HY] = 10 3 M K a = 3 . 47 10 3 is the stronger acid? 1. Acid Y is stronger. correct 2. I would have to know if X or Y is a strong acid. 3. Acid X is stronger. 4. They have the same strength. Explanation: Acid Y has a larger K a value and is there- fore stronger. 002 10.0 points Consider the equilibrium 2 SO 2 (g) + O 2 (g) 2 SO 3 (g) If the partial pressure of SO 2 is increased, what happens to the partial pressure of O 2 ? 1. decreases correct 2. remains the same 3. increases 4. Unable to determine Explanation: When the partial pressure of SO 2 increases, the partial pressure of O 2 will decrease. Ac- cording to Le Chateliers principle, an in- crease in the partial pressure of a reactant shifts the equilibrium toward products, de- creasing the partial pressure of the other re- actant O 2 . 003 10.0 points What is the maximum possible value of the vant Hoff factor for a solution of the strong electrolyte FeCl 3 that is so dilute that no ion association occur? 1. i must be an odd number. 2. i = 4 correct 3. i = 6 4. i = 0 5. i = 2 Explanation: FeCl 3 Fe 3+ + 3 Cl Each mole of FeCl 3 can produce 4 moles of ions. 004 10.0 points A dissolution process is exothermic if the amount of energy released in bringing about ? interactions is greater than the sum of the amounts of energy absorbed in overcom- ing ? and ? interactions. 1. solute-solute; crystal lattice; solvent- solvent 2. solvent-solute; solute-solute; crystal lat- tice 3. solvent-solute; solute-solute; solvent- solvent correct 4. solute-solute; solvent-solvent; solvent- solute 5. solvent-solvent; solute-solute; solvent- solute Explanation: In the course of dissolution, you disrupt solute-solute interactions and solvent-solvent interactions in order to create new solvent- solute interactions. So you can imagine that you have to invest energy to break up solute- solute interactions and solvent-solvent inter- actions. However, you get energy back in Version 383 Exam 2 Sutcliffe (52410) 2 the creation of solvent-solute interactions. If your investment in solute-solute and solvent- solvent interactions is less than your return in solvent-solute interactions, excess energy (as heat) will be produced and the reaction will be exothermic. 005 10.0 points Consider the reaction A + B C + D K c = 29 . 372 . What is the K c value for the reaction 2 A + 2 B 2 C + 2 D ? 1. 2. 58 . 744 3. . 034 4. 29 . 372 5. 863 correct Explanation: 006 10.0 points According to the Bronsted-Lowry concept of acids and bases, which of the following state- ments about a base is NOT true?...
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- Spring '09