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Worksheets

Redox

Total questions: 20

Worksheet time: 40mins

Name
Class
Date
1.

What is the oxidation number of chlorine in HClO?

a)

0

b)

-1

c)

+1

d)

+5

2.

Oxidation is the _________ of electrons.

a)

loss

b)

gain

c)

sharing

d)

transfer

3.

Reduction is the ___________ of electrons.

a)

loss

b)

gain

c)

sharing

d)

transfer

4.

What is the oxidation number of N2?

a)

-3

b)

0

c)

+4

d)

-1

5.

In the reaction Zn + 2HCl --> ZnCl2 + H2

which element is oxidized?

a)

Zinc

b)

Hydrogen

c)

Chlorine

d)

None

6.

In the reaction: 2 Ca + O2 --> 2 CaO

calcium is __________

a)
Reduced
b)
Oxidized
7.
Which statement is true:
Mg → Mg2+ + 2e–
a)
Mg gains 2 electrons
b)

Mg loses 2 electrons

c)

Mg stays the same

d)

Mg gains 1 electrons

8.
What substance is oxidized in the following reaction?
4Fe + 3O2 --> 2Fe2O3
a)
Iron
b)
Fluorine
c)
Oxygen
9.

In the reaction: Zn + Cu2+ →\rightarrow Zn2+ + Cu,

the Cu2+

a)

is reduced

b)

is oxidized

10.

In a redox reaction, the reducing agent will

a)

lose an electron and be reduced

b)

lose an electron and be oxidized

c)

gain an electron and be reduced

d)

gain an electron and be oxidized

11.

In the reaction: 2 Mg + O2 →\rightarrow 2 MgO,

the magnesium is the

a)

oxidizing agent and is reduced

b)

oxidizing agent and is oxidized

c)

reducing agent and is reduced

d)

reducing agent and is oxidized

12.

Given the reaction: Ca + CuS →\rightarrow CaS + Cu,

What is the correct reduction half-reaction?

a)

Cu+2 + 2e-1 →\rightarrow Cu0

b)

Cu+2 →\rightarrow Cu0 + 2e-1

c)

Cu0 + 2e-1 →\rightarrow Cu+2

d)

Cu0 →\rightarrow Cu+2 + 2e-1

13.
     In the reaction Zn + H2O --> ZnO2 + H2
 which element, if any, is oxidized? 
a)
Zinc
b)
Hydrogen
c)
Oxygen
d)
None
14.

Substance that is reduced is called the...

a)

reducing agent

b)

oxidation number

c)

combustion

d)

oxidizing agent

15.

Substance that reduces another substance by losing electrons.

a)

reducing agent

b)

half-reaction

c)

electronegative atom

d)

oxidizing agent

16.

What is a half-reaction of this equation, Na + Cl --> NaCl ?

a)

Cl° + e-1 --> Cl-1

b)

Cl° - e-1 --> Cl-1

c)

Na+1 --> Na° + e-1

d)

Na° + Cl°--> Na+1Cl-1

17.

Oxidation states for

CaCrO4

a)

Ca=+2, Cr=+6, O=-2

b)

Ca=+2, Cr=+4, O=-2

c)

Ca=+2, Cr=+6, O=-8

d)

Ca=+4, Cr=+6, O=-2

18.

Which is oxidized and which is reduced?

Ca + Na2O → Na + CaO

a)

Oxidized: Na

Reduced: O

b)

Oxidized: Ca

Reduced: O

c)

Oxidized: Na

Reduced: Ca

d)

Oxidized: Ca

Reduced: Na

19.

Which is oxidized and which is reduced?

CaCl2 + O2 → CaClO3

a)

Oxidized: Ca

Reduced: O

b)

Oxidized: Cl

Reduced: O

c)

Oxidized: Ca

Reduced: Cl

d)

Oxidized: O

Reduced: Cl

20.

What is a correct half reaction for the following reaction:

2 Al + N2 ----> 2 AlN

a)

Al0 + 3 e- --> Al+3

b)

N0 --> N+2 + 2 e-1

c)

Al+3 + 3 e-1 --> Al0

d)

N0 + 3 e-1 --> N-3