Question 1

  1. Consider the following equilibrium.
    4NH3(g) + 3O2(g)

/ View Full Image /
  1. 2N2(g) + 6H2O(g)
    Suppose 0.30 mol of NH3 and 0.40 mol of oxygen are added to a 5.0-L container. If x mol of water is present at equilibrium, what is the equilibrium concentration of oxygen?Answer

0.40 - 0.50x
0.30 - 0.50x
0.08 - 0.10x
0.06 - 0.13x
0.40 -
/ /
/ View Full Image /
x

4 points

Question 2

  1. At 298 K, the value of Kc for the reaction H2(g) + Br2(g)

/ View Full Image /
  1. 2HBr(g) is 2.0 × 1019. What is Kc for HBr(g)

/ View Full Image /
  1. ½H2(g) + ½Br2(g)?Answer

-2.0 × 1019
5.0 × 10-20
2.2 × 10-10
4.0 × 10-38
1.0 × 1019

4 points

Question 3

  1. Consider the following equilibrium:
    2NH3(g)

/ View Full Image /
  1. N2(g) + 3H2(g); ΔH = 92 kJ
    What change should be made in order to increase the value of Kp for this reaction? Answer

Increase the temperature.
Decrease the temperature.
Increase the pressure.
Decrease the pressure.
Nothing; Kp cannot be changed.

4 points

Question 4

  1. One method for the decomposition of carbon dioxide proceeds as follows:
    2CO2(g)

/ View Full Image /
  1. 2CO(g) + O2(g); ΔH= 559 kJ
    Which of the following changes will cause an increase in the equilibrium concentration of CO?Answer

increasing the pressure of the system at constant temperature
adding more O2 to the system
removing CO2 from the system
increasing the temperature of the system
adding a catalyst

4 points

Question 5

  1. Which of the following correctly describes the equilibrium constant for the gas-phase reaction between H2 and O2 to form gaseous H2O?Answer

Kc =
/ /
/ View Full Image /
Kc =
/ /
/ View Full Image /
Kc =
/ /
/ View Full Image /
Kc =
/ /
/ View Full Image /
Kc = [H2O]

4 points

Question 6

  1. Consider the following equilibrium:
    C2H6(g) + C5H12(g)

/ View Full Image /
  1. CH4(g) + C6H14(g); Kp = 9.57 at 500 K
    Suppose 19.6 g each of CH4, C2H6, C5H12, and C6H14 are placed in a 40.0-L reaction vessel at 500 K. What is the value of Qp?Answer

1.00
9.57
0.637
1.57
0.104

4 points

Question 7

  1. Carbon tetrachloride may react with oxygen to produce chlorine and carbonyl chloride.
    2CCl4(g) + O2(g)

/ View Full Image /
  1. 2COCl2(g) + 2Cl2(g); Kc = 9.9 × 1051
    What is Kc for the following equilibrium?
    COCl2(g) + Cl2(g)

/ View Full Image /
  1. CCl4(g) + ½O2(g)Answer

-9.9 × 1051
1.0 × 10-26
9.9 × 10-51
1.0 × 10-52
5.0 × 10-53

4 points

Question 8

  1. What effect will spraying liquid water into a system have if NH3 is far more soluble in water than is N2 or H2?
    N2(g) + 3H2(g)

/ View Full Image /
  1. 2NH3(g)Answer

This will not affect the system.
More NH3(g) will form.
More N2(g) will form.
Less NH3(g) will form.
More H2(g) will form.

4 points

Question 9

  1. Hydrogen iodide undergoes decomposition according to the equation
    2HI(g)

/ View Full Image /
  1. H2(g) + I2(g)
    The equilibrium constant Kp at 500 K for this equilibrium is 0.060. Suppose 0.637 mol of HI is placed in a 8.50-L container at 500 K. What is the equilibrium concentration of H2(g)?
    (R = 0.0821 L · atm/(K · mol))Answer

0.075 M
0.037 M
0.13 M
0.015M
0.61 M

4 points

Question 10

  1. Which of the following statements is incorrect concerning the addition of a catalyst to an equilibrium reaction system?Answer

The catalyst increases the rate of both the forward and the reverse reaction.
If the reactants are capable of forming many different products, a catalyst may selectively speed up one reaction over another.
The catalyst speeds up the attainment of equilibrium.
The catalyst increases the yield of the products.
The catalyst is not consumed in either the forward or the reverse reaction.

4 points

Question 11

  1. For the reaction Br2(g) + Cl2(g)

/ View Full Image /
  1. 2BrCl(g), at equilibrium, it is found that the concentrations of Br2, Cl2, and BrCl are 0.124 M, 0.199 M, and 8.59 × 10-4M, respectively. What is the value of Kc?Answer

3.50 × 10-2
3.01 × 10-5
3.32 × 104
1.20 × 10-4
2.86 × 101

4 points

Question 12

  1. For the endothermic reaction 2CO2(g) + N2(g)

/ View Full Image /
  1. 2NO(g) + 2CO(g), the conditions that favor maximum conversion of the reactants to products areAnswer

high temperature and high pressure.
high temperature, pressure being unimportant.
high temperature and low pressure.
low temperature and high pressure.
low temperature and low pressure.

4 points

Question 13

  1. Which expression correctly describes the equilibrium constant Kc for the following reaction?
    4NH3(g) + 5O2(g)

/ View Full Image /
  1. 4NO(g) + 6H2O(g)Answer

/ /
/ View Full Image /
/ /
/ View Full Image /
/ /
/ View Full Image /
/ /
/ View Full Image /
/ /
/ View Full Image /

4 points

Question 14

  1. Which of the following represents a dynamic equilibrium?Answer

an open pan of boiling water
two people of equal mass balanced on the ends of a seesaw
a coin spinning in mid-air
a stoppered flask half full of water
an object traveling at a constant speed

4 points

Question 15

  1. For the reaction given below, 2.00 mol of A and 3.00 mol of B are placed in a 6.00-L container.

/ View Full Image /
/ View Full Image /
/ View Full Image /

  1. At equilibrium, the concentration of A is 0.218 mol/L. What is the concentration of B at equilibrium?Answer

0.218 mol/L
0.269 mol/L
0.500 mol/L
0.436 mol/L
none of these

4 points

Question 16

  1. For the equilibrium N2O4(g)

/ View Full Image /
  1. 2NO2(g), at 298 K, Kp = 0.15. For this reaction system, it is found that the partial pressure of N2O4 is 3.5

/ View Full Image /
  1. 10-2 atm at equilibrium. What is the partial pressure of NO2 at equilibrium? (R = 0.0821 L · atm/(K · mol))Answer

0.0053 atm
23 atm
0.072 atm
0.0018 atm
4.8 atm

4 points

Question 17

  1. In which of the following reactions does an instantaneous increase in the volume of the reaction vessel favor formation of the products?Answer

MgO(s) + CO2(g)
/ /
/ View Full Image /
MgCO3(s)
PCl5(g)
/ /
/ View Full Image /
PCl3(g) + Cl2(g)
H2(g) + I2(g)
/ /
/ View Full Image /
2HI(g)
N2(g) + O2(g)
/ /
/ View Full Image /
2NO(g)
N2(g) + 3H2(g)
/ /
/ View Full Image /
2NH3(g)

4 points

Question 18

  1. A sample of ammonia gas was allowed to come to equilibrium at 400 K.
    2NH3(g)

/ View Full Image /
  1. N2(g) + 3H2(g)
    At equilibrium, it was found that the concentration of H2 was 0.0270 M, the concentration of N2 was 0.00901 M, and the concentration of NH3 was 0.0920 M. What is Kc for this equilibrium?Answer

2.65 × 10-3
3.97 × 10-3
1.58 × 10-5
2.10 × 10-5
4.90 × 10-1

4 points

Question 19

  1. Consider the reaction represented by the equation N2(g) + 3H2(g)

/ View Full Image /
  1. 2NH3(g). What happens to the equilibrium position when an inert gas is added to this system (as represented above) at equilibrium?Answer

If the container is rigid, nothing happens to the equilibrium position. If the container is fitted with a movable piston, the equilibrium position shifts.
If the container is rigid, the equilibrium position shifts. If the container is fitted with a movable piston, nothing happens to the equilibrium position.
The equilibrium position shifts no matter what the container is like.
Nothing happens to the equilibrium position no matter what the container is like.
The value of the equilibrium constant must be known to answer this question.

4 points

Question 20

  1. Consider the following reaction:

/ View Full Image /
/ View Full Image /
/ View Full Image /
  1. (K = 1.00

/ View Full Image /
  1. 10-2)
    Given that 1.00 mol of HF(g), 0.239 mol of H2(g), and 0.750 mol of F2(g) are mixed in a 5.00-L flask, determine the reaction quotient, Q.Answer

Q = 0.0359
Q = 0.179
Q = 0.0448
Q = 1.99
none of these

4 points

Question 21

  1. For which of the following systems at equilibrium and at constant temperature will increasing the volume have no effect on the equilibrium?Answer

SO2Cl2(g)
/ /
/ View Full Image /
SO2(g) + Cl2(g)
CO(g) + H2O(g)
/ /
/ View Full Image /
CO2(g) + H2(g)
COCl2(g)
/ /
/ View Full Image /
CO(g) + Cl2(g)
I2(g)
/ /
/ View Full Image /
2I(g)
C(s) + CO2(g)
/ /
/ View Full Image /
2CO(g)

4 points

Question 22

  1. Consider the following equilibrium:
    O2(g) + 2F2(g)

/ View Full Image /
  1. 2OF2(g); Kp = 2.3 × 10-15
    Which of the following statements is true?Answer

If the reaction mixture initially contains only OF2(g), then the total pressure at equilibrium will be less than the total initial pressure.
If the reaction mixture initially contains only O2(g) and F2(g), then at equilibrium, the reaction mixture will consist of essentially only OF2(g).
If the reaction mixture initially contains only O2(g) and F2(g), then the total pressure at equilibrium will be greater than the total initial pressure.
If the reaction mixture initially contains only OF2(g), then at equilibrium, the reaction mixture will consist of essentially only O2(g) and F2(g).
For this equilibrium, Kc = Kp.

4 points

Question 23

  1. At 800 K, Kc for the following equilibrium is 4.2 × 10-3.
    2HgO(s)

/ View Full Image /
  1. 2Hg(l) + O2(g)
    Suppose 38.9 g of mercury (II) oxide is placed in a sealed 1.50-L vessel at 800 K. What is the partial pressure of oxygen gas at equilibrium? (R = 0.0821 L · atm/(K · mol))Answer

0.28 atm
38 atm
6.9 atm
0.0042 atm
3.4 atm

4 points

Question 24

  1. Which of the following can we determine by using an equilibrium constant for a gaseous reaction system?
    1. the effect of changing the volume of the reaction system
    2. the extent of a reaction at equilibrium
    3. the direction of a reaction upon adding both reactants and productsAnswer

1 only
2 only
3 only
1 and 2 only
1, 2, and 3

4 points

Question 25

  1. Solid HgO, liquid Hg, and gaseous O2 are placed in a glass bulb and allowed to reach equilibrium.
    2HgO(s)

/ View Full Image /
  1. 2Hg(l) + O2(g); ΔH = 181.6 kJ
    The amount of Hg(l) in the bulb could be increasedAnswer

by removing some HgO(s).
by adding some HgO(s)
by increasing the temperature.
by increasing the pressure.
by adding an inert gas.