Perk Learning Lab, MGCCC

Created by Tara L. Moore

GENERAL CHEMISTRY, 5^th ed., Whitten, Davis & Peck

Chapter 17 Review Quiz

Matching

1. Activity e. Heterogeneous equilibria i. van’t Hoff
2. Chemical equilibrium f. Homogeneous equilibria equation
3. Dynamic equilibrium g. LeChatelier’s Principle
4. Equilibrium constant, K h. Reaction Quotient, Q

1. The mass action expression under any set of conditions (not necessarily equilibrium)
2. An equilibrium in which processes occur continuously, with no net change
3. A dimensionless quantity whose magnitude is equal to molar concentration in an ideal solution, equal partial pressure in an ideal gas mixture
4. Equilibria involving species in more than one phase
5. If a stress is applied to a system at equilibrium, the system shifts in the direction that reduces the stress
6. A quantity that indicates the extent to which a reversible reaction occurs; its magnitude is equal to the mass action expression at equilibrium

Multiple Choice- CyberEd Multimedia Courseware

7. The term equilibrium is best described as a(n) _____.
1. Solution
2. Force
3. Balance
4. Overflow

8. At equilibrium, the forward and reverse reactions occur at equal rates.
1. True
2. False

9. A chemical reaction that requires or absorbs heat is _____.
1. Endothermic
2. Exothermic
3. Reversible
4. None of the above

10. Chemical equilibrium is a dynamic process. This means that _____.
1. The reaction will stop when equilibrium is achieved
2. The reaction does not stop when equilibrium is achieved
3. The reaction has gone to completion
4. There is no chemical reaction taking place

11. When a system has reached chemical equilibrium, the concentrations of the reactants and products _____.
1. Remain constant
2. Continue to change
3. Are equal
4. Are zero

12. In a homogeneous equilibrium system, all reactants and products are in _____.
1. Different physical states
2. The same physical state
3. The same equilibrium positions
4. Different equilibrium positions

13. Which of the following reactions is heterogeneous?
1. N₂O₅ (g) à NO₂ (g) + NO₃ (g)
2. FeO (s) + CO(g) à Fe(s) + CO₂(g)
3. 2NO₂(g) à N₂O₄(g)
4. 2HI(g) à H₂ (g) + I₂(g)

14. Solids and liquids are excluded from equilibrium expressions because _____.
1. They are too reactive to deal with
2. They only react under low pressure
3. Their concentrations vary
4. Their concentrations do not change

15. What is the equilibrium constant for the following reaction?

2NOCl (g) à 2NO (g) + Cl₂(g)

1. K = [NOCl]²/ [NO]² [Cl₂]
2. K = [NO]² [Cl₂]/ [NOCl]²
3. K = [NO] [Cl]²/[NOCl]
4. K = 2[NOCl]/2[Cl₂][NO]

16. Although there may be many possible positions for a reaction, there is only one equilibrium constant (K) for any particular reaction at a given temperature.
1. True
2. False

17. The equilibrium constant (K) is not affected by changes in temperature.
1. True
2. False

18. The value of the equilibrium constant is ?

K = [0.50 M]/ [0.25M]

1. K = 5.0
2. K = 3.0
3. K = 2.0
4. K = 1.0

19. Using the chemical equations and equilibrium concentrations (at 500K) below, calculate the equilibrium constant for [CO]= 2.00M, [H₂] = 1.00 M,

[CH₃OH] = 21.0M

CO(g) + 2H₂ à CH₃OH(g)

a. K = 10.5

b. K = 7.0

c. K = 5.25

d. K = 0.095

20. If K = 1.3 then _____.
1. The reaction system at equilibrium contains mostly reactants
2. The reaction system at equilibrium contains mostly products
3. The reaction system at equilibrium contains roughly equal concentrations of reactants and products
4. Not enough information is provided to answer the question

21. If K = 1 x 10^-12 then _____.
1. The reaction system at equilibrium contains mostly reactants
2. The reaction system at equilibrium contains mostly products
3. The reaction system at equilibrium contains roughly equal concentrations of reactants and products
4. Not enough information is provided to answer the question

22. If a reaction system at equilibrium contains mostly product then _____.
1. K = 1
2. K >> 1
3. K << 1
4. K = 0

23. The equilibrium constant (K) depends on the initial concentration of reactants and products.
1. True
2. False

24. The reaction quotient (Q) indicates _____.
1. The equilibrium constant of a reaction
2. The rate of a reaction
3. The position of a reaction relative to equilibrium
4. The energy of a reaction at equilibrium

25. To determine if a reaction is at equilibrium, compare the reaction quotient (Q), to _____.
1. The equilibrium position
2. Le Chatelier’s constant
3. The dissociation constant
4. The equilibrium constant

26. If Q> K, then _____.
1. The reaction is at equilibrium
2. The reaction continues in the forward direction
3. The reaction continues in the reverse direction
4. The reaction has stopped

27. If Q = K, then _____.
1. The reaction is at equilibrium
2. The reaction continues in the forward direction
3. The reaction continues in the reverse direction
4. The reaction has stopped

28. Adding reactant to a system at equilibrium will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

29. Adding product to a system at equilibrium will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

30. Removing product from a system at equilibrium will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

31. Removing reactant from a system at equilibrium will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

32. Increasing the pressure on a system will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

33. Increasing the number of molecules in a fixed volume results in _____.
1. Increase volume
2. Decreased pressure
3. Increased pressure
4. Decreased temperature

34. Increasing the volume of a closed system at equilibrium will _____.

1. Increase the pressure
2. Decrease the pressure
3. Decrease the temperature
4. Not change the equilibrium conditions

35. For the following reaction in a closed container, a decrease in volume will _____.

2NO₂ (g) ßà N₂O₄ (g)

1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

36. For the following reaction in a closed container, a decrease in pressure will _____.

2SO₂ (g) + O₂ (g) ß à 2SO₃ (g)

1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

37. For the following reaction in a closed container, an increase in pressure will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

38. An increase in temperature for an exothermic reaction will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

39. A decrease in temperature for an endothermic reaction will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

40. A decrease in temperature for an exothermic reaction will _____.
1. Shift the reaction to the left
2. Shift the reaction to the right
3. Not affect equilibrium
4. Not enough information is provided to answer the question

41. A change in pressure may affect the equilibrium position but has no effect on the equilibrium constant.
1. True
2. False

42. A change in temperature may affect the equilibrium position but has no effect on the equilibrium constant.
1. True
2. False

ANSWERS

1. h

2. c

3. a

4. e

5. g

6. d

7. c

8. a

9. b

10. b

11. a

12. b

13. b

14. d

15. b

16. a

17. b

18. c

19. a

20. c

21. a

22. b

23. b

24. c

25. d

26. c

27. a

28. b

29. a

30. b

31. a

32. d

33. c

34. b

35. b

36. a

37. c

38. a

39. a

40. b

41. a

42. b