Download Chemistry 100 Quiz 4-

1 of 3
Instructor: Nicole Stevens
Winter 2008
Chemistry 100
Quiz 4--Part 1
You may write on this part of the test, but MARK YOUR FINAL ANSWERS on a separate bubble sheet!
1.
2.
Which of the descriptions below best represents a reduction?
a. iron (II) ion becomes an iron (III) ion
d.
b. calcium atom becomes a calcium ion
e.
c. sodium ion becomes a sodium atom
f.
fluorine ion becomes a fluorine atom
all of these are reduction reactions.
none of these are reduction reactions
Which of the following reactions is an oxidation-reduction (redox) reaction?
a. HCl + NaOH ↔ NaCl + H2O
d. HNO3 + Zn ↔ Zn(NO3)2 + H2
b. Cu(NO3)2 + Na2SO4 ↔ 2NaNO3 + CuSO4
c. MgSO4 + ZnCO3 ↔ ZnSO4 + MgCO3
e.
all of these are redox reactions
f.
none of these are redox reactions
3.
Which of the following represents the oxidation number of nitrogen in sodium nitrite?
a. -1
d. -3
b. +1
e. +5
c. +3
f. -5
4.
Which is the substance being reduced in the following reaction?
Cl2 + 2NaBr → 2NaCl + Br2
a. chlorine
d. chlorine and bromine are both reduced
b. sodium
e. sodium and chlorine are both reduced
c. bromine
f. bromine and sodium are both reduced
5.
Which substance is the oxidizing agent in the following reaction?
Fe + CuSO4 → FeSO4 + Cu
a. oxygen
d. copper
b. iron
e. not an oxidation-reduction reaction
c. sulfur
For each example on the left, select the correct oxidation number of
Oxidation numbers may be used more than once!
a.
6. carbonate ion
b.
c.
7. carbonite ion
d.
e.
8. carbon tetrahydride (methane)
f.
g.
9. elemental carbon
h.
i.
10. dicarbon tetrahydrogen monoxide
j.
carbon from the list on the right.
-4
-3
-2
-1
0
+1
+2
+3
+4
+5
Questions 11 and 12 will count as extra credit!
11. In a dry cell battery, what is the substance being oxidized?
a. lead
b. cadmium
c. manganese
d.
e.
f.
nickel
zinc
magnesium
Instructor: Nicole Stevens
2 of 3
Winter 2008
Chemistry 100
Quiz 4--Part 1
You may write on this part of the test, but MARK YOUR FINAL ANSWERS on a separate bubble sheet!
12. Which of the following statements is true?
a. classic photography depends on the oxidation of silver ions to silver metal
b. cut fruit browns because an enzyme oxidizes the iron present in the fruit to an "organic rust"
c. the Statue of Liberty is green because the nickel metal is oxidized to a green product
d. when any element becomes an ion, it has been oxidized
e. when iron metal is reduced in a reaction with oxygen gas, the result is rust (iron oxide)
f. all of the above are true
3 of 3
Instructor: Nicole Stevens
Winter 2008
Name
Chemistry 100
Quiz 4--Part 2
Write directly on this part of the test. SHOW ALL WORK!
I.
Iron (II) phosphate reacts with sodium hyposulfite to form iron (II) hyposulfite and sodium phosphate.
a.
Write the balanced equation.
Fe3(PO4)2 + 3Na2SO2 → 3FeSO2 + 2Na3PO4
b.
c.
4 pts
Assign oxidation numbers to each product and reactant.
2.5 pts
Products:
Reactants:
Fe = +2
→
Fe = +2
1/2 pt. each element
P = +5
→
P = +5
O = -2
→
O = -2
Oxidation numbers may
Na = +1
→
Na = +1
be written above equation
S = +2
→
S = +2
Is this an oxidation-reduction (redox) reaction? If so, name the substance being oxidized,
the substance being reduced, the oxidizing agent and the reducing agent.
1 pt
Since no oxidation numbers change from one side of the equation to the other,
this is not a redox reaction.
II.
Propylene gas (C3H6) reacts with oxygen during combustion to form carbon dioxide and water vapor.
a. Write the balanced equation for this reaction, including states of matter.
2C3H6 (g) + 9O2 (g) → 6CO2 (g) + 6H20 (g)
4 pts
b. Assign oxidation numbers to each product and reactant in this reaction.
Products:
C = -2
H = +1
O=0
c.
→
→
→
Reactants:
C = +4
H = +1
O = -2
1.5 pts
1/2 pt. each element
Is this an oxidation-reduction (redox) reaction? If so, name the substance being oxidized,
the substance being reduced, the oxidizing agent and the reducing agent.
Yes, this is a redox reaction
Carbon goes from oxidation number -3 to +4, so it is being oxidized
and acts as the reducing agent.
Oxygen goes from oxidation number 0 to -2, so it is being reduced
and acts as the oxidizing agent.
(1/2 pt. each for what's being oxidized, being reduced,
oxidizing and reducing agents)
2 pts