CHM 112 Exam I A Chap 11-13 13 pt Fall 2012
1. Closed book, but open calculator. Write your name on the back of each page.
2. Show calculations and logic throughout to receive full credit.
3. Make appropriate use of significant figures and units.
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1. (0.4 pt) Given the data in table below, calculate the average rate of H O decomposition
during the period from 600 to 1200 seconds. (Source: General Chemistry, Petrucci et al.)
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Time (s) [H O ] (M)
0 2.32
200 2.01
400 1.72
600 1.49
1200 0.98
1800 0.62
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2. (2 pt) Given these data for the reaction of Cl with NO: Initial rate
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Cl (g) + 2 NO (g) ÿ 2 NOCl(g) Exp# [NO ] (M) [Cl ] (M) (M/s)
1 0.0125 0.0255 2.27 x 10!5
2 0.0125 0.0510 9.08 x 10!5
3 0.0250 0.0255 4.54 x 10!5
Be sure to explain the logic for your answers.
a) Write a general rate law for the reaction.
b) Use the initial rate data to write the specific rate law consistent with the data. Make sure you
solve to obtain a numerical value for k.
c) Write a chemical rxn. for the reactant side of the rate limiting step in the rxn. mechanism.
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d) What is the initial rate of the rxn. with 0.090 M 2Cl and 1.50 M NO?
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