Chem1BExam2sampleTestKey

Chem1BExam2sampleTestKey - Chem 1B Exam 2 Name October 6,...

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Chem 1B Name Lab T W Th Exam 2 October 6, 2009 Instructions: For all mathematical problems, show your work. Give the basic formula (if there is one), rearrange it if necessary, plug in data with units, round properly to the correct number of significant figures, and place a box around the answer. For essay questions, be complete, but concise. Complete sentences with proper spelling and punctuation are expected. Useful information: K w = 1.0 × 10 -14 1. (4 pts.) Write the equilibrium constant expression for the following reaction. 3CN 1- (aq) + 2MnO 4 1- (aq) + H 2 O( l ) 3CNO 1- (aq) + 2MnO 2 (s) + 2OH 1- (aq) K = [CNO 1- ] 3 [OH 1- ] 2 [CN 1- ] 3 [MNO 4 1- ] 2 2. (6 pts.) Calculate the value of the equilibrium constant for the reaction 2CF 4 (g) + 4H 2 O(g) 2CO(g) + 8HF(g) + O 2 (g) given CF 4 (g) + 2H 2 O(g) CO 2 (g) + 4HF(g) K = 5.9 × 10 23 CO(g) + 1/2O 2 (g) CO 2 (g) K = 1.3 × 10 35 Show all work. 2CF 4 (g) + 4H 2 O(g) 2CO 2 (g) + 8HF(g) K = (5.9 × 10 23 ) 2 2CO 2 (g) 2CO(g) + O 2 (g) K = (1.3 × 10 35 ) -2 2CF 4 (g) + 4H 2 O(g) 2CO(g) + 8HF(g) + O 2 (g) K = (5.9 × 10 23 ) 2 × (1.3 × 10 35 ) -2 = 2.1 × 10 -23 3. (5 pts. Consider the following equilibrium system: 6 CO 2 (g) + 6 H 2 O( l ) C 6 H 12 O 6 (s) + 6 O 2 (g) H = 2826 kJ Predict the direction in which the equilibrium will shift (if any) if: (a) P CO 2 is decreased shifts left (b) temperature is increased shifts right (c) O 2 is removed shifts right (d) total pressure is increased no change (e) some H 2 O( l ) is added no change
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4. (10 pts.) Consider the following reaction: 2Cr 3+ (aq) + Fe(s) 2Cr 2+ (aq) + Fe 2+ (aq) K = 10.5 An iron nail is added to a solution having the concentrations [Cr
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Chem1BExam2sampleTestKey - Chem 1B Exam 2 Name October 6,...

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