Practice Material for Exam 2 for UC2 Spring 2010 (1)

Practice Material for Exam 2 for UC2 Spring 2010 (1) -...

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University Chemistry II Spring, 2010 Practice Exam #2 This set of questions will give you some great practice, but in no way replaces the value of practicing homework, problems worked in class and the in-class projects. We suggest you do those first until you think you have them mastered, and then put all notes, books, music and food aside, time yourself and see how you do on this set of questions. Allow only on the average of 2-3 minutes/question and see how you do. 1. Which of the following is not true regarding a gas phase chemical reaction at equilibrium? a) The reaction must be carried out in a closed system. b) The reaction continues in the forward direction and the reverse direction at the same rate. c) If the reaction has a large equilibrium constant the reaction rapidly reaches equilibrium. d) The reaction must be reversible so that reactants continue to be converted to product while product continues to be converted back to reactants. 2. What is the equilibrium expression (K c ) for the synthesis of NO 2 ? 4 NH 3 (g) + 7 O 2 (g) 4 NO 2 (g) + 6 H 2 O(g) a) K c = [NO 2 ] 4 b) K c = [NH 3 ] 4 [O 2 ] 7 c) K c = [NO 2 ] 4 [H 2 O] 6 d) K c = [NH 3 ] 4 [O 2 ] 7 [NH 3 ] 4 [O 2 ] 7 [NO 2 ] 4 [H 2 O] 6 [NH 3 ] 4 [O 2 ] 7 [NO 2 ] 4 3. Calculate the equilibrium constant, K c for: A(g) + 2B(g) C(g) if the equilibrium concentrations are [A] eq = 4.5x10 - 5 M, [B] eq = 2.2x10 - 2 M, and [C] eq = 9.4x10 - 3 M. a) 4.3x10 5 b) 72 c) 1.4x10 - 2 d) 23.0 4. At 1000 K the reaction: N 2 (g) + 3 H 2 (g) 2 NH 3 (g) has a K c value of 2.4x10 - 3 . What is the value of the equilibrium constant for the following reaction? 2/3 NH 3 (g) 1/3 N 2 (g) + H 2 (g) a) 7.23x10 7 b) 417 c) 139 d) 7.47 e) 1.38x10 - 8 5. What is the value of K p at 298 K for the reaction below, given the data that follows at 298 K? ½ CH 4 (g) + H 2 O(g) ½ CO 2 (g) + 2 H 2 (g) CO 2 (g) + H 2 (g) CO(g) + H 2 O(g) K p = 9.80x10 - 6 CO(g) + 3 H 2 (g) CH 4 (g) + H 2 O(g) K p = 8.00x10 24 a) 1.28x10 - 20 b) 5.89x10 - 14 c) 2.04x10 25 d) 1.13x10 - 10 6. At 500 o C, the equilibrium constant K p for the reaction: N 2 (g) + 3 H 2 (g) 2 NH 3 (g) is 1.45x10 - 5 . What is the value of K c ? HINT: K p = K c (RT) n R = 0.08206 L atm/mol K a) 3.60x10 - 9 b) 17.1 c) 0.0583 d) 0.0244 e) 1.16x10 - 4 7. In which of the following reaction types does the equilibrium expression contain all of the species that appear in the balanced equation? a)
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This note was uploaded on 03/29/2010 for the course CHEM 1123 taught by Professor Paul during the Spring '06 term at Arkansas.

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Practice Material for Exam 2 for UC2 Spring 2010 (1) -...

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