Sample Exam EP 6 December 2009 Midterm

ep 6 review dec 2009

Matching

Match each item with the correct statement below.
a. oxidation number c. oxidizing agent
b. half-reaction d. reducing agent


____ 1. substance that accepts electrons

____ 2. substance that donates electrons

____ 3. integer related to the number of electrons under an atom's control

____ 4. reaction showing either the reduction or the oxidation reaction

Match each item with the correct statement below.
a. Choose coefficients to make the change in oxidation number equal to 0.
b. Make the electron changes of both half-reactions equal.
c. Assign oxidation numbers to all the atoms.
d. Write the equation showing ions separately.


____ 5. the first step in balancing a redox reaction by the oxidation-number-change method

____ 6. the next-to-the-last step in balancing a redox reaction by the oxidation-number-change method

____ 7. the first step in balancing a redox reaction by the half-reaction method

____ 8. the next-to-the-last step in balancing a redox reaction by the half-reaction method


Match each item with the correct statement below.
a. anode d. half-cell
b. battery e. cathode
c. fuel cell


____ 9. the electrode at which oxidation occurs

____ 10. one part of a voltaic cell in which either oxidation or reduction occurs

____ 11. the electrode at which reduction occurs

____ 12. a group of cells that are connected together

____ 13. a voltaic cell in which a fuel substance undergoes oxidation and from which electrical energy is obtained continuously

Match each item with the correct statement below.
a. electrode d. voltaic cell
b. electrolysis e. dry cell
c. salt bridge


____ 14. a tube containing a conducting solution

____ 15. a conductor in a circuit that carries electrons to or from a substance other than a metal

____ 16. an electrochemical cell that is used to convert chemical energy to electrical energy

____ 17. a voltaic cell in which the electrolyte is a paste

____ 18. a process in which electrical energy is used to bring about a chemical change

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

____ 19. When iron oxide becomes iron, what type of reaction occurs?
a. oxidation c. neutralization
b. reduction d. combination


____ 20. Which statement is true about the following reaction?
S + Cl SCl
(Hint: Chlorine is the more electronegative element.)
a. Sulfur is reduced to SCl . c. Chlorine is oxidized to SCl .
b. Chlorine is reduced to SCl . d. Sulfur is the oxidizing agent.


____ 21. What is defined as the charge an atom would have in a compound if its bonding electrons were assigned to the more electronegative atom?
a. reduction number c. valence
b. oxidation number d. electropositivity


____ 22. Which atom has a change in oxidation number of –3 in the following redox reaction?
K Cr O + H O + S KOH + Cr O + SO
a. K c. O
b. Cr d. S


____ 23. In the following unbalanced reaction, which atom is oxidized?
HNO + HBr NO + Br + H O
a. hydrogen c. oxygen
b. nitrogen d. bromine


____ 24. Which element decreases its oxidation number in the following reaction?
BiCl + Na SO 2NaCl + BiSO
a. bismuth
b. chlorine
c. oxygen
d. No element decreases its oxidation number.


____ 25. Which element decreases its oxidation number in the following reaction?
I + 2KCl 2KI + Cl
a. iodine
b. potassium
c. chlorine
d. No element decreases its oxidation number.


____ 26. What is the oxidation half-reaction for the following unbalanced redox equation?
Cr O + Fe Cr + Fe
a. Cr Cr O c. Fe Fe
b. Fe Fe d. Cr O Cr


____ 27. What is shown by a half-reaction?
a. oxidation or reduction of an element c. decomposition of an ion or molecule
b. neutralization of an ion or molecule d. none of the above


____ 28. What is the ionic form of the following unbalanced equation?
MnO + HNO Mn(NO ) + H O
a. MnO + HNO Mn + NO + H O
b. MnO + H + NO MnNO + H O
c. MnO + H + NO Mn + NO + H O
d. Mn + O + H + NO Mn + NO + H O


____ 29. Identify the pair of metals that lists the more easily oxidized metal on the left.
a. Ag, Na c. Ca, Al
b. Fe, K d. K, Li


____ 30. At which electrode does oxidation occur in a voltaic cell?
a. anode only
b. cathode only
c. both anode and cathode
d. either anode or cathode, depending on the metal


____ 31. Which electrode is labeled as positive in a voltaic cell?
a. anode only c. both anode and cathode
b. cathode only d. neither anode nor cathode


____ 32. What is the electrode in the center of the most common dry cell made of?
a. copper c. iron
b. zinc d. graphite


____ 33. What metal is oxidized in the most common dry cell?
a. copper c. iron
b. zinc d. carbon


____ 34. What is reduced in the most common dry cell?
a. copper c. manganese dioxide
b. zinc d. carbon


____ 35. When a lead storage battery discharges, the concentration of ____.
a. sulfuric acid increases
b. sulfuric acid decreases
c. lead sulfate in the battery decreases
d. lead sulfate in the battery remains constant


____ 36. What is the electrolyte in the hydrogen-oxygen fuel cell?
a. sulfuric acid c. potassium hydroxide
b. hydrochloric acid d. sodium hydroxide


____ 37. What standard reduction electrode has a half-cell potential of 0.00 V?
a. oxygen c. lithium
b. hydrogen d. fluorine


____ 38. At which electrode (anode or cathode) does oxidation occur in an electrolytic cell?
a. anode c. both
b. cathode d. neither


ep 6 review dec 2009
Answer Section

MATCHING

1. ANS: C DIF: L1 REF: p. 634 OBJ: 20.1.1

2. ANS: D DIF: L1 REF: p. 634 OBJ: 20.1.2

3. ANS: A DIF: L1 REF: p. 639 OBJ: 20.2.1

4. ANS: B DIF: L1 REF: p. 650 OBJ: 20.3.1

5. ANS: C DIF: L1 REF: p. 648, p. 649
OBJ: 20.3.1

6. ANS: A DIF: L1 REF: p. 648, p. 649
OBJ: 20.3.1

7. ANS: D DIF: L1 REF: p. 650, p. 651
OBJ: 20.3.2

8. ANS: B DIF: L1 REF: p. 650, p. 651
OBJ: 20.3.2

9. ANS: A DIF: L1 REF: p. 665 OBJ: 21.1.2

10. ANS: D DIF: L1 REF: p. 665 OBJ: 21.1.2

11. ANS: E DIF: L1 REF: p. 665 OBJ: 21.1.2

12. ANS: B DIF: L1 REF: p. 668 OBJ: 21.1.4

13. ANS: C DIF: L1 REF: p. 669 OBJ: 21.1.5

14. ANS: C DIF: L1 REF: p. 665 OBJ: 21.1.2

15. ANS: A DIF: L1 REF: p. 665 OBJ: 21.1.2

16. ANS: D DIF: L1 REF: p. 665 OBJ: 21.1.2

17. ANS: E DIF: L1 REF: p. 667 OBJ: 21.1.3

18. ANS: B DIF: L1 REF: p. 678 OBJ: 21.3.1

MULTIPLE CHOICE

19. ANS: B DIF: L1 REF: p. 632 OBJ: 20.1.1

20. ANS: B DIF: L2 REF: p. 633, p. 634
OBJ: 20.1.2

21. ANS: B DIF: L1 REF: p. 639 OBJ: 20.2.1

22. ANS: B DIF: L1 REF: p. 643 OBJ: 20.2.2

23. ANS: D DIF: L2 REF: p. 643 OBJ: 20.2.2

24. ANS: D DIF: L2 REF: p. 643 OBJ: 20.2.2

25. ANS: A DIF: L2 REF: p. 643 OBJ: 20.2.2

26. ANS: B DIF: L2 REF: p. 650, p. 651
OBJ: 20.3.2

27. ANS: A DIF: L1 REF: p. 650 OBJ: 20.3.2

28. ANS: C DIF: L3 REF: p. 650, p. 651
OBJ: 20.3.2

29. ANS: C DIF: L2 REF: p. 664 OBJ: 21.1.1

30. ANS: A DIF: L1 REF: p. 665 OBJ: 21.1.2

31. ANS: B DIF: L1 REF: p. 665 OBJ: 21.1.2

32. ANS: D DIF: L1 REF: p. 667 OBJ: 21.1.3

33. ANS: B DIF: L1 REF: p. 667 OBJ: 21.1.3

34. ANS: C DIF: L1 REF: p. 667 OBJ: 21.1.3

35. ANS: B DIF: L2 REF: p. 668 OBJ: 21.1.4

36. ANS: C DIF: L1 REF: p. 669 OBJ: 21.1.5

37. ANS: B DIF: L1 REF: p. 672 OBJ: 21.2.2

38. ANS: A DIF: L2 REF: p. 679 OBJ: 21.3.1