Download Chpt 20:21 review

Name: ______________________
Class: _________________
Date: _________
Chpt 20/21 review
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. If an atom is reduced in a redox reaction, what must happen to another atom in the system?
a. It must be oxidized.
b. It must be reduced.
c. It must be neutralized.
d. Nothing needs to happen to another atom in the system.
____
2. Which of these metals tends to resist losing electrons to corrosion?
a. aluminum
b. iron
c. platinum
d. zinc
____
3. In which of the following types of reaction are electrons gained?
a. decomposition
b. oxidation
c. neutralization
d. reduction
____
4. What particles are transferred in an oxidation-reduction reaction?
a. protons
b. ions
c. electrons
d. atoms
____
5. How does a block of zinc attached to a steel ship hull protect the hull from corrosion?
a. Zinc is a better reducing agent so it corrodes instead of the iron corroding.
b. Zinc is a better oxidizing agent so it corrodes instead of the iron corroding.
c. The zinc carries electrons toward the iron so that the iron cannot react.
d. The zinc carries electrons away from the iron so that the iron cannot react.
____
6. Cu → Cu
+ 2 eThe equation above represents a reaction that can be classified as ____.
a. redox
b. hydrolysis
c. reduction
d. oxidation
____
7. Which type of reaction does Sn
a. oxidation
b. reduction
c. hydrolysis
d. redox
2+
2+
→ Sn
4+
represent?
1
ID: A
Name: ______________________
____
____
ID: A
8. What is the reducing agent in the following reaction?
2Na + 2H 2 O → 2NaOH + H 2
a.
b.
Na
H2 O
c.
d.
NaOH
H2
9. What process occurs during the corrosion of iron?
a. Iron is oxidized.
b. Iron is reduced.
c. Iron (III) is oxidized.
d. Iron (III) is reduced.
____ 10. Why is oxygen reduced in the reaction of hydrogen with oxygen to make water?
a. Oxygen pulls electrons toward itself.
b. Oxygen pushes electrons toward the hydrogens.
c. Oxygen absorbs a proton.
d. Oxygen releases a proton.
____ 11. The
a.
b.
c.
d.
oxidation number of magnesium in magnesium chloride is ____.
–1
0
+1
+2
____ 12. The
a.
b.
c.
d.
oxidation number of bromine in bromine gas is ____.
+1
–1
0
–2
____ 13. In which of the following species is the oxidation number of sulfur less than 6?
a. SO 3
b.
Na 2 SO 4
c.
SO 4
d.
S2 O 4
2−
2−
____ 14. In the following unbalanced reaction, which atom is reduced?
H 2 O + Cl 2 + SO 2 → HCl + H 2 SO 4
a.
b.
c.
d.
hydrogen
oxygen
chlorine
sulfur
2
Name: ______________________
ID: A
____ 15. In the following unbalanced reaction, which atom is oxidized?
HNO 3 + HBr → NO + Br 2 + H 2 O
a.
b.
c.
d.
hydrogen
nitrogen
oxygen
bromine
____ 16. Which of the following chemical equations represents an oxidation-reduction reaction?
a. Mg(OH) 2 + 2HCl → MgCl 2 + 2H2 O
b.
BiCl 2 + Na 2 SO 4 → 2NaCl + BiSO 4
c.
CH4 + 2O2 → CO 2 + 2H2 O
d.
3NaOH + H 3 PO 4 → Na 3 PO 4 + 3H 2 O
____ 17. Which element increases its oxidation number in the following reaction?
3KOH + H 3 PO 4 → K 3 PO 4 + 3H 2 O
a.
b.
c.
d.
oxygen
potassium
phosphorus
no changes in oxidation number
____ 18. The oxidation number of what atom or ion decreases in the following reaction?
I 2 + 2KCl → 2KI + Cl 2
a.
b.
c.
d.
iodine atom
potassium atom
chlorine ion
potassium ion
____ 19. Which of the following chemical equations represents a redox reaction?
a. 2Na + 2H2 O → 2NaOH + H2
b. HCl + KOH → KCl + H2 O
c. AgNO3 (aq) + NaCl(aq) → ΝaNO3 (aq) + AgCl(s) + H2 O(l)
d. Fe3+ + 3NO3 – + 3Na+ + 3OH– → Fe(OH)3 + 3Na+ + 3NO3 –
+
____ 20. What is the coefficient for H when this half-reaction is balanced?
+
2+
H + MnO 2 → Mn + H 2 O
a.
b.
c.
d.
1
2
3
4
3
Name: ______________________
ID: A
____ 21. What is the reduction half-reaction for the following unbalanced redox equation?
2−
+
Cr 2 O 7 + NH 4 → Cr 2 O 3 + N 2
a.
Cr 2 O 3 → Cr 2 O 7
b.
Cr 2 O 7
c.
NH
d.
N 2 → NH 4
+
4
2−
2−
→ Cr 2 O 3
→ N2
+
____ 22. What is the key factor in defining a reaction as an oxidation-reduction reaction?
a. transfer of electrons between atoms
b. oxygen as one of the reactants
c. making and breaking ionic bonds
d. precipitation of solid from the reaction solution
____ 23. The
a.
b.
c.
d.
half-reaction method is particularly useful for balancing which type of equation?
dissociation
acid-base
redox
combustion
____ 24. Which term describes the following process?
2Fe(s) + O 2 (g) + 2H 2 O(l) → 2Fe(OH) 2 (s)
4Fe(OH) 2 (s) + O 2 (g) +2H 2 O(l) → 4Fe(OH) 3 (s)
a.
b.
c.
d.
salt hydrolysis
electrolysis
corrosion
buffering
____ 25. Which of the following is an oxidation half-reaction?
2+
4+
a. Sn → Sn + 2e −
b. Cl 2 + 2e − → 2Cl −
+
c.
O 2 + 4H + 4e − → 2H 2 O
d.
Fe
3+
+ e − → Fe
2+
____ 26. Which of these metal’s ions are most easily reduced ?
a. iron
b. mercury
c. aluminum
d. potassium
____ 27. How is the cell potential of a voltaic cell calculated?
a. Ecell = Ered − Eoxid
b. Ecell = Eoxid − Ered
c. Ecell = Ered + Eoxid
d. Ecell = Ered ÷ Eoxid
4
Name: ______________________
ID: A
2+
____ 28. In a zinc-copper cell, Zn | Zn (1M) || Cu
2+
a. Cu (aq)
b. Cu(s)
c. Zn(s)
2+
d. Zn (aq)
2+
(1M) | Cu, of which material is the negative made?
____ 29. How can a redox reaction be used as a source of electrical energy?
a. Two half-reactions must be physically separated.
b. One half-reaction must involve two metals.
c. Two half-reactions must involve more than one electron.
d. One half-reaction must use a metal wire electrode.
____ 30. Which electrode is labeled as positive in a voltaic cell?
a. anode
b. cathode
c. standard hydrogen electrode
d. mercury electrode
____ 31. →The half reaction at a barium electrode is: Ba2+ + 2e − → Ba
For a cell using a barium electrode and a hydrogen electrode, E° = 2.90 V. What is the standard reduction
potential of the barium electrode?
a.
b.
c.
d.
−2.90 V
−1.45 V
1.45 V
2.90 V
____ 32. Which of the following factors does NOT affect the voltage produced in a voltaic cell?
a. metal of the electrodes
b. concentrations of ions
c. temperature
d. pressure
____ 33. What is the electrode in the center of the most common dry cell made of?
a. copper
b. zinc
c. iron
d. graphite
____ 34. What is oxidized in a graphite dry cell battery?
a. copper
b. zinc
c. iron
d. carbon
____ 35. What is reduced in a graphite dry cell battery?
a. copper
b. zinc
c. manganese dioxide
d. carbon
5
Name: ______________________
ID: A
____ 36. Why can’t a lead storage battery be recharged indefinitely?
a. A direct current must pass through the cells.
b. The electrodes lose lead sulfate.
c. It is difficult to reverse the direction of current flow.
d. The electrolyte is too expensive.
____ 37. The
a.
b.
c.
d.
substance reduced in a hydrogen-oxygen fuel cell is ____.
water
hydrogen
hydrogen peroxide
oxygen
____ 38. What causes current to flow in an electrolytic cell?
a. an outside power source
b. a spontaneous redox reaction
c. a nonspontaneous redox reaction
d. difference in potential between the two half-cells
____ 39. By
a.
b.
c.
d.
convention, which electrodes are labeled as the positive electrodes in electrochemical cells?
cathode in electrolytic cells, anode in voltaic cells
anode in electrolytic cells, cathode in voltaic cells
cathode in both types of cells
anode in both types of cells
____ 40. What is the purpose of the electrolyte in a cell used to electrolyze water?
a. It reacts with water to produce hydrogen.
b. It reacts with water to produce oxygen.
c. It carries current between the electrodes.
d. It neutralizes the ions produced at the electrodes.
____ 41. What is produced in the electrolysis of brine?
a. chlorine gas, sodium hydroxide, and hydrogen gas
b. chlorine gas and hydrogen gas only
c. chlorine gas and oxygen gas only
d. chlorine gas and sodium only
6
ID: A
Chpt 20/21 review
Answer Section
MULTIPLE CHOICE
1. ANS: A
PTS: 1
DIF: L1
REF: p. 693
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: knowledge
2. ANS: C
PTS: 1
DIF: L1
REF: p. 697
OBJ: 20.1.2 Explain how the presence of salts and acids accelerates the corrosion of metals.
BLM: comprehension
3. ANS: D
PTS: 1
DIF: L1
REF: p. 694
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: knowledge
4. ANS: C
PTS: 1
DIF: L1
REF: p. 694
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: knowledge
5. ANS: A
PTS: 1
DIF: L2
REF: p. 698
OBJ: 20.1.2 Explain how the presence of salts and acids accelerates the corrosion of metals.
BLM: comprehension
6. ANS: D
PTS: 1
DIF: L2
REF: p. 694
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: application
7. ANS: A
PTS: 1
DIF: L2
REF: p. 694
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: application
8. ANS: A
PTS: 1
DIF: L2
REF: p. 695
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: application
9. ANS: A
PTS: 1
DIF: L2
REF: p. 697
OBJ: 20.1.2 Explain how the presence of salts and acids accelerates the corrosion of metals.
BLM: comprehension
10. ANS: A
PTS: 1
DIF: L2
REF: p. 696
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: comprehension
11. ANS: D
PTS: 1
DIF: L2
REF: p. 702
OBJ: 20.2.1 State the general rule for assigning oxidation numbers.
BLM: analysis
12. ANS: C
PTS: 1
DIF: L2
REF: p. 702
OBJ: 20.2.1 State the general rule for assigning oxidation numbers.
BLM: comprehension
13. ANS: D
PTS: 1
DIF: L2
REF: p. 702 | p. 703
OBJ: 20.2.1 State the general rule for assigning oxidation numbers.
BLM: analysis
14. ANS: C
PTS: 1
DIF: L2
REF: p. 706
OBJ: 20.2.2 Define oxidation and reduction in terms of a change in oxidation number.
BLM: application
1
ID: A
15. ANS: D
PTS: 1
DIF: L2
REF: p. 706
OBJ: 20.2.2 Define oxidation and reduction in terms of a change in oxidation number.
BLM: analysis
16. ANS: C
PTS: 1
DIF: L2
REF: p. 707
OBJ: 20.3.1 Identify the two classes of chemical reactions. BLM: analysis
17. ANS: D
PTS: 1
DIF: L2
REF: p. 701
OBJ: 20.2.2 Define oxidation and reduction in terms of a change in oxidation number.
BLM: analysis
18. ANS: A
PTS: 1
DIF: L2
REF: p. 706
OBJ: 20.2.2 Define oxidation and reduction in terms of a change in oxidation number.
BLM: analysis
19. ANS: A
PTS: 1
DIF: L2
REF: p. 709
OBJ: 20.3.1 Identify the two classes of chemical reactions. BLM: application
20. ANS: D
PTS: 1
DIF: L2
REF: p. 712
OBJ: 20.3.2 Balance a redox equation using the oxidation-number-change method.
BLM: analysis
21. ANS: B
PTS: 1
DIF: L2
REF: p. 712
OBJ: 20.3.2 Balance a redox equation using the oxidation-number-change method.
BLM: application
22. ANS: A
PTS: 1
DIF: L1
REF: p. 692
OBJ: 20.1.1 Describe what happens to a substance that undergoes oxidation and a substance that
undergoes reduction.
BLM: knowledge
23. ANS: C
PTS: 1
DIF: L2
REF: p. 712
OBJ: 20.3.2 Balance a redox equation using the oxidation-number-change method.
BLM: comprehension
24. ANS: C
PTS: 1
DIF: L2
REF: p. 697
OBJ: 20.1.2 Explain how the presence of salts and acids accelerates the corrosion of metals.
BLM: comprehension
25. ANS: A
PTS: 1
DIF: L2
REF: p. 712
OBJ: 20.3.2 Balance a redox equation using the oxidation-number-change method.
BLM: comprehension
26. ANS: B
PTS: 1
DIF: L2
REF: p. 729
OBJ: 21.1.1 Identify the type of chemical reaction involved in all electrochemical processes.
BLM: comprehension
27. ANS: A
PTS: 1
DIF: L2
REF: p. 737
OBJ: 21.2.1 Identify what causes the electrical potential of an electrochemical cell.
BLM: comprehension
28. ANS: C
PTS: 1
DIF: L2
REF: p. 731
OBJ: 21.1.2 Describe how a voltaic cell produces electrical energy.
BLM: comprehension
29. ANS: A
PTS: 1
DIF: L1
REF: p. 730
OBJ: 21.1.2 Describe how a voltaic cell produces electrical energy.
BLM: knowledge
30. ANS: B
PTS: 1
DIF: L1
REF: p. 730
OBJ: 21.1.2 Describe how a voltaic cell produces electrical energy.
BLM: knowledge
2
ID: A
31. ANS: A
PTS: 1
DIF: L2
REF: p. 739
OBJ: 21.2.2 Determine the standard reduction potential of a half-cell.
BLM: application
32. ANS: D
PTS: 1
DIF: L2
REF: p. 737
OBJ: 21.2.1 Identify what causes the electrical potential of an electrochemical cell.
BLM: comprehension
33. ANS: D
PTS: 1
DIF: L1
REF: p. 733
OBJ: 21.1.3 Identify the current applications that use electrochemical processes to produce
energy.
BLM: knowledge
34. ANS: B
PTS: 1
DIF: L1
REF: p. 732
OBJ: 21.1.3 Identify the current applications that use electrochemical processes to produce
energy.
BLM: knowledge
35. ANS: C
PTS: 1
DIF: L1
REF: p. 732
OBJ: 21.1.3 Identify the current applications that use electrochemical processes to produce
energy.
BLM: knowledge
36. ANS: B
PTS: 1
DIF: L1
REF: p. 734
OBJ: 21.1.3 Identify the current applications that use electrochemical processes to produce
energy.
BLM: knowledge
37. ANS: D
PTS: 1
DIF: L2
REF: p. 735
OBJ: 21.1.3 Identify the current applications that use electrochemical processes to produce
energy.
BLM: comprehension
38. ANS: A
PTS: 1
DIF: L1
REF: p. 746
OBJ: 21.3.1 Distinguish between electrolytic and voltaic cells.
BLM: knowledge
39. ANS: B
PTS: 1
DIF: L1
REF: p. 746
OBJ: 21.3.1 Distinguish between electrolytic and voltaic cells.
BLM: knowledge
40. ANS: C
PTS: 1
DIF: L2
REF: p. 747
OBJ: 21.3.2 Describe some applications that use electrolytic cells.
BLM: comprehension
41. ANS: A
PTS: 1
DIF: L2
REF: p. 748
OBJ: 21.3.2 Describe some applications that use electrolytic cells.
BLM: comprehension
3
electrical
electrical
electrical
electrical
electrical