Northrup's Chem 112 Section
Chem 1120 - Chapter 14: Chemical Equilibrium
Practice Quiz 2
1. Identify the INCORRECT statement below regarding chemical equilibrium:
2. Calculator problem - Nitrogen reacts with hydrogen to form ammonia:
N2(g) + 3 H2(g) <==> 2 NH3(g)
At a certain temperature the equilibrium constant is Kc = 2.0. An equilibrium mixture is
contain concentrations of N2 equal to 0.15 M and H2 equal to 0.30 M. What is
concentration of NH3 in this mixture?
3. Write the appropriate equilibrium constant expression Kc for the following reaction:
2 CO(g) + O2(g) <==> 2 CO2(g)
4. Suppose we rewrote the balanced reaction in Problem #3 as:
5. When Kc >> 1 for a chemical reaction:
6. In the rearrangement reaction:
cyclopropane <==> propene
the equilibrium constant at a certain temperature is Kc = 3.0. A reaction vessel initial having
cyclopropane concentration [cyclopropane]0 = 2.0 M and no propene is allowed to come to
equilibrium. What will be the concentration of propene at equilibrium?
For Problems #7 - 11
A proposed mechanism for the decomposition of ozone is:
7. Which step is rate-determining?
8. Which species is (are) an unstable intermediate?
9. Which species is a catalyst?
10. Which is the best overall rate law consistent with this mechanism?
11. The properly written overall balanced equation is:
12. Identify the INCORRECT statement below:
13. For the reaction:
2 H2(g) + O2(g) <-----> 2 H2O(g)
14. In a given mixture of N2, Cl2 and NCl3
gases, the following partial
pressures are found:
PN2 = 0.17 atm, PCl2 = 0.43 atm, PNCl3 = 7.0
15. Which of the following changes can affect the value of the equilibrium
16. A collection of gases N2(g), Cl2(g) and
NCl3(g) are in equilibrium in a
N2(g) + 3 Cl2(g) <-----> 2 NCl3(g)
17. In the gas phase reaction:
PCl3(g) + Cl2(g) <-----> PCl5(g)
Kc = 1.9
18. A simple reaction is the cis-trans isomerization of an alkene
cis-alkene <-----> trans-alkene
19. For the reaction:
H2 + Cl2 <-----> 2 HCl
1)e 2)d 3)d 4)b 5)d 6)c 7)b 8)c 9)c 10)d 11)a 12)c 13)d 14)b 15)c 16)a 17)e 18)b 19)b
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