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Worksheets

Chemistry Unit 9 Review

Total questions: 40

Worksheet time: 2hrs 44mins

Name
Class
Date
1.

What is the oxidation number for Br in the compound KBr?

a)

+5

b)

+3

c)

+1

d)

-1

2.

What is the oxidation number for Br in the compound KBrO3?

a)

+5

b)

+3

c)

+1

d)

-1

3.

What is the oxidation number for Br in the compound KBrO?

a)

+5

b)

+3

c)

+1

d)

-1

4.

What is the oxidation number for Br in the compound KBrO2?

a)

+5

b)

+3

c)

+1

d)

-1

5.

What is the oxidation number for S in the compound K2SO4?

a)

+6

b)

+4

c)

+2

d)

-2

6.

What is the oxidation number for S in the compound SO3?

a)

+6

b)

+4

c)

+2

d)

-2

7.

What is the oxidation number for S in the compound K2S2O3?

a)

+6

b)

+4

c)

+2

d)

-2

8.

What is the oxidation number for S in the compound CS2?

a)

+6

b)

+4

c)

+2

d)

-2

9.

What is the oxidation number for C in the compound C3H8?

a)

-4

b)

-2.67

c)

-1.33

d)

0

10.

What is the oxidation number for C in the compound C10H8?

a)

-2.67

b)

-1.25

c)

-0.80

d)

0

11.

Ca(s) + H2O(l) --> H2(g) + Ca(OH)2(aq)

In this chemical equation, the oxidized substance is _____ and the reduced substance is _____.

a)

Ca(s); O in H2O(l)

b)

O in H2O(l); Ca(s)

c)

Ca(s); H in H2O(l)

d)

H in H2O(l); Ca(s)

12.

Chose the correct set of balancing coefficients for the chemical equation in question #11 (Ca(s) + H2O(l) --> H2(g) + Ca(OH)2(aq))

a)

2, 1, 1, 2

b)

1, 2, 2, 1

c)

1, 2, 1, 1

d)

1, 1, 2, 2

13.

In this chemical equation, the oxidized substance is _____ and the reduced substance is _____.

CaC2(s) + H2O(l) --> C2H2(g) + Ca(OH)2(aq)

a)

Ca(s); O in H2O(l)

b)

C; Ca(s)

c)

Ca(s); C

d)

There is no oxidation & reduction here

14.

Chose the correct set of balancing coefficients for the chemical equation in question #13 (CaC2(s) + H2O(l) --> C2H2(g) + Ca(OH)2(aq))

a)

2, 1, 1, 2

b)

1, 2, 2, 1

c)

1, 2, 1, 1

d)

1, 1, 2, 2

15.

In this chemical equation, the oxidized substance is _____ and the reduced substance is _____.

Na2S(aq) + Mg(NO3)2(aq) --> MgS(s) + NaNO3(aq)

a)

Na+ ; Mg2+

b)

N ; Mg2+

c)

S2- ; N

d)

There is no oxidation & reduction here

16.

Chose the correct set of balancing coefficients for the chemical equation in question #15 (Na2S(aq) + Mg(NO3)2(aq) --> MgS(s) + NaNO3(aq))

a)

2, 1, 1, 1

b)

1, 2, 1, 1

c)

1, 1, 2, 1

d)

1, 1, 1, 2

17.

Choose the pair below that will react with each other

a)

Cu2+ and Mg2+

b)

Pb2+ and Mg

c)

Zn and Sn

d)

Fe and Zn2+

18.

Choose the pair below that will react with each other

a)

Cu2+ and Sn

b)

Pb2+ and Ag

c)

Ni and Al3+

d)

Fe and Zn2+

19.

Choose the pair below that will react with each other

a)

H2 and Zn

b)

Au and Ag+

c)

Mg and H+

d)

Pb and Zn2+

20.

One of the chemical equations below is a correct representation of an oxidation-reduction reaction. The other two are not. Choose the correct one.

a)

Zn2+(aq) + Pb(s) --> Pb2+(aq) + Zn(s)

b)

Zn2+(aq) + Pb2+(aq) --> Pb2+(aq) + Zn2+(aq)

c)

Pb2+(aq) + Zn(s) --> Zn2+(aq) + Pb(s)

d)

None of these are correct

21.

One of the chemical equations below is a correct representation of an oxidation-reduction reaction. The other two are not. Choose the correct one.

a)

2Ag+(aq) + Pb(s) --> Pb2+(aq) + 2Ag(s)

b)

2Ag+(aq) + Pb2+(aq) --> Pb2+(aq) + 2Ag+(aq)

c)

Pb2+(aq) + 2Ag(s) --> 2Ag+(aq) + Pb(s)

d)

None of these are correct

22.

One of the chemical equations below is a correct representation of an oxidation-reduction reaction. The other two are not. Choose the correct one.

a)

Ni2+(aq) + Sn(s) --> Sn2+(aq) + Ni(s)

b)

Ni2+(aq) + Sn2+(aq) --> Ni(s) + Sn4+(aq)

c)

Ni2+(aq) + Sn(s) --> Sn2+(aq) + Ni(s)

d)

None of these are correct

23.

Choose the correct value of the cell potential (voltage), in volts, for a copper/zinc cell.

a)

-0.42 V

b)

+0.42 V

c)

-1.10 V

d)

+1.10 V

24.

Choose the correct value of the cell potential (voltage), in volts, for a silver/lithium cell.

a)

+3.85 V

b)

-3.85 V

c)

+2.25 V

d)

-2.25 V

25.

Choose the correct value of the cell potential (voltage), in volts, for a magnesium/H2SO4 cell.

a)

-3.37 V

b)

-2.37 V

c)

+2.27 V

d)

+3.37 V

26.

If a small lamp is illuminated with a 9.00 V battery and the lamp draws 250. mA of current, the power of the circuit is (a)   watts.

27.

If the circuit in question 25 (9.00 V battery and the lamp draws 250. mA of current) runs for 5.00 minutes, the energy consumed by the circuit is (a)   joules.

28.

The light bulb in question 25 was an incandescent bulb. Most of the energy released by the bulb was in the form of

a)

heat

b)

heat and light

c)

light

d)

heat, light, and voltage

29.

If a LED was wired to a 9.00 V battery and a 500-ohm resistor, and if the LED operated for 5.00 minutes, the power of this circuit would be _________ the power of the circuit in question 26.

a)

higher than

b)

lower than

c)

the same as

d)

first higher than, then lower than

30.

The energy consumed by the circuit in question 29 (LED was wired to a 9.00 V battery and a 500-ohm resistor, and if the LED operated for 5.00 minutes) will be _________ the energy consumed by the circuit in question 26

a)

higher than

b)

lower than

c)

the same as

d)

first higher than, then lower then

31.

The LED in question 29 released most of the energy in the form of

a)

heat

b)

heat and light

c)

light

d)

heat, light, and voltage

32.

The heat of combustion of methane (natural gas) is 891 kJ/mole. The burning of 10.0 g of methane will release (a)   kJ.

33.

If we used the amount of energy from question 32 (557 kJ) to power a 75 watt circuit (like a group of light bulbs), the circuit would run for ____________ .

a)

roughly 30 minutes

b)

roughly 1 hour

c)

roughly 2 hours

d)

roughly 4 hours

34.

Electric utilities charge their customers by the kilowatt-hour. (a)   kJ is the equivalent of one kilowatt-hour.

35.

The heat of combustion of methane (CH4) is 891 kJ/mole. (a)   grams of methane must be burned to release an amount of energy that is equivalent to one kilowatt-hour.

36.

The four principal parts of an electrochemical cell are these:

a)

Anode, cathode, electrolyte, container

b)

Anode, cathode, container, external wire

c)

Anode, cathode, electrolyte, external wire

d)

Anode, cathode, external wire, voltmeter

37.

The electrolyte does what job in an electrochemical cell?

a)

Keeps the overall cell electrically neutral

b)

Provides a path for the electron transfer

c)

Provides a location for the oxidation and reduction to occur

d)

All of the above

38.

What happens at the cathode in an electrochemical cell?

a)

Oxidation

b)

Reduction

c)

Both oxidation and reduction

d)

Neither oxidation nor reduction

39.

Choose the statement that is the best comparison of electrochemical cells and batteries

a)

Electrochemical cells involve only oxidation or reduction; batteries involve both.

b)

Batteries can provide power to circuits; electrochemical cells can't.

c)

Electrochemical cells are made of liquids; batteries are made of solids.

d)

A battery is made of one or more electrochemical cells.

40.

Choose the most accurate statement about batteries.

a)

A battery's voltage is fixed until it dies, but the current it produces will vary.

b)

A battery will produce a constant current until it dies, but its voltage will vary.

c)

A battery will produce a constant level of power but not a constant level of voltage.

d)

Any battery is rechargeable.