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Balanced Redox Reactions

Total questions: 20

Worksheet time: 2hrs 58mins

Name
Class
Date
1.
     In the reaction Zn + H2O --> ZnO2 + H2
 which element, if any, is oxidized? 
a)
Zinc
b)
Hydrogen
c)
Oxygen
d)
None
2.
What substance is oxidized in the following reaction?
4Fe + 3O2 --> 2Fe2O3
a)
Iron
b)
Fluorine
c)
Oxygen
3.
If in a reaction, copper is reduced; its number of electrons has:
a)
Increased
b)
Decreased
c)
Remained Constant
d)
Varies Randomly
4.
If an atom loses electrons during a chemical reaction, the atom was:
a)
Oxidized
b)
Reduced
c)
Neutralized
d)
Precipitated
5.

What element is being Reduced?

a)

N

b)

H

c)

O

d)

S

6.
What is oxidation number of Cr in Cr2O72-?
a)
-2
b)
+2
c)
+6
d)
+12
7.
What is oxidation number of O in O2 ?
a)
0
b)
-2
c)
+1
d)
+2
8.

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


Balance the following ACIDIC reactions using changing oxidation number 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

9.

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


Balance the following reactions using changing oxidation number method.

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

How many electrons water compound produced in the reaction?

a)

10

b)

9

c)

8

d)

7

10.

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

11.

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

12.

What element is being Oxidized?

a)

N

b)

H

c)

O

d)

S

13.

What element is being Reduced?

a)

N

b)

H

c)

O

d)

S

14.

What are the coefficients when the equation is balanced?

a)

2 + 3 --> 2 + 3 + 4

b)

1 + 3 --> 1 + 3 + 2

c)

2 + 4 --> 2 + 3 + 2

d)

1 + 1 --> 1 + 1 + 1

15.

What element is being Oxidized?

a)

I

b)

H

c)

S

d)

O

16.

What are the coefficients when the equation is balanced?

a)

1 + 1 + 1 --> 2 + 1 + 3

b)

2 + 2 + 2 --> 4 + 2 + 3

c)

1 + 2 + 1 --> 2 + 2 + 3

d)

1 + 1 + 1 --> 1 + 1 + 1

17.

What element is being reduced?

a)

I

b)

H

H

c)

S

S

d)

O

O

18.
What is oxidation number of Cr in Cr2O72-?
a)
-2
b)
+2
c)
+6
d)
+12
19.
What is oxidation number of H in CaH2?
a)
+1
b)
-1
c)
0
d)
+2
20.
What is the oxidation number of N in NO2-1?
a)
-3
b)
+4
c)
-2
d)
+3