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Week 7: Balancing REDOX reactions

Total questions: 14

Worksheet time: 29mins

Name
Class
Date
1.

What is the oxidation number of oxygen in water?

a)

-1

b)

-2

c)

0

d)

+1

e)

+2

2.
Is calcium oxidized or reduced in the following reaction? 
2CaO--> 2Ca + O2
a)
Oxidized
b)
Reduced
3.
In the reaction
2Ca(s) + O2(g) --> 2CaO(s), calcium is __________
a)
Reduced
b)
Synthesized
c)
Oxidized
d)
None of the above
4.
     In the reaction Zn + H2O --> ZnO2 + H2
 which element, if any, is oxidized? 
a)
Zinc
b)
Hydrogen
c)
Oxygen
d)
None
5.
What substance is oxidized in the following reaction?
4Fe + 3O2 --> 2Fe2O3
a)
Iron
b)
Fluorine
c)
Oxygen
6.
If in a reaction, copper is reduced; its number of electrons has:
a)
Increased
b)
Decreased
c)
Remained Constant
d)
Varies Randomly
7.
If an atom loses electrons during a chemical reaction, the atom was:
a)
Oxidized
b)
Reduced
c)
Neutralized
d)
Precipitated
8.
What element is being Reduced?
a)
N
b)
H
c)
O
d)
S
9.
What is oxidation number of Cr in Cr2O72-?
a)
-2
b)
+2
c)
+6
d)
+12
10.
What is oxidation number of O in O2 ?
a)
0
b)
-2
c)
+1
d)
+2
11.

WRITE THIS OUT ON PAPER, YOU MAY USE THE ANSWER TO THIS PROBLEM AGAIN IN ANOTHER QUESTION:


Balance the following ACIDIC reactions using the half-reaction method.

MnO4(aq) + H+(aq) + I (aq) → Mn2+(aq) + I2(s)


Water is a product of this reaction. What is the coefficient of water in the final balanced equation?

a)

8

b)

5

c)

2

d)

16

12.

WRITE THIS OUT ON PAPER, YOU MAY USE THE ANSWER TO THIS PROBLEM AGAIN IN ANOTHER QUESTION:


Balance the following reactions using the half-reaction method.

MnO4(aq) + H+(aq) + I (aq) → Mn2+(aq) + I2(s)

How many electrons did you cross out on both side?

a)

1 e-

b)

2 e-

c)

5 e-

d)

10 e-

13.

WRITE THIS OUT ON PAPER, YOU MAY USE THE ANSWER TO THIS PROBLEM AGAIN IN ANOTHER QUESTION:


Consider the following REDOX reaction:

Cl2(g) → ClO(aq) + Cl(aq) (basic solution)

How many OH- molecules did you add to the reactant side of this reaction when balancing?

a)

1

b)

2

c)

3

d)

4

14.

WRITE THIS OUT ON PAPER, YOU MAY USE THE ANSWER TO THIS PROBLEM AGAIN IN ANOTHER QUESTION:

Consider the following REDOX reaction:

Cl2(g) → ClO(aq) + Cl(aq) (basic solution)

Which species is the result of oxidation?

a)

Cl

b)

ClO