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Electromotive Force : Basics

Total questions: 25

Worksheet time: 13mins

Name
Class
Date
1.
What does the double line mean?
Zn/Zn+2 // Cu+2/Cu
a)
anode
b)
cathode
c)
salt bridge
d)
substance in contact
2.

What reaction occurs at the anode?

Ag+/Ag = 0.80V

Ni2+/Ni = -0.25V

a)

Ag+ + e- →Ag

b)

Ag → Ag+ + e-

c)

Ni2+ + 2e- → Ni

d)

Ni → Ni2+ + 2e-

3.

Galvanic cells convert

a)

mechanical energy in to electrical energy

b)

potential energy in to electrical energy

c)

electrical energy in to chemical energy

d)

chemical energy in to electrical energy

4.

Reference electrode that is universally used whose reduction potential value is zero is

a)

SHE

b)

Calomel electrode

c)

chlorine electrode

d)

standard zinc electrode

5.

What is oxidation?

a)

It is the gain of electrons.

b)

It is the loss of electrons.

c)

It is the creation of electrons.

d)

It is the destruction of electrons.

6.

What is reduction?

a)

It is the gain of electrons.

b)

It is the loss of electrons.

c)

It is the creation of electrons.

d)

It is the destruction of electrons.

7.

What is a half-reaction?

a)

It is a reaction at equilibrium where half of the substances are reactants and half of the substances are products.

b)

It is the reaction that occurs when the switch of a galvanic cell is open.

c)

It shows EITHER the reduction component or the oxidation component of a redox reaction.

d)

It shows BOTH the reduction and oxidation components of a redox reaction.

8.

What is a standard half-cell?

a)

It is one cell that comprises half of a whole battery.

b)

It is a cell containing only a metal bar with no aqueous ion solution.

c)

It is a cell containing only an aqueous ion solution and no metal bar.

d)

It is a cell that generates half of a volt of electricity.

9.

Electrons always flow from

a)

cathode to anode

b)

anode to cathode

10.
An iron nail is put into a solution of copper nitrate, iron is above copper in the activity series of metals, what will happen?
a)
iron will be reduced
b)
bubbles of oxygen gas will form on iron nail
c)
the iron nail will become copper plated
d)
no reaction occurs
11.

Given their standard reduction potentials, which of the species is going to be oxidized?

Cu2+/Cu = 0.34V

Zn2+/Zn = -0.76V

a)

Cu

b)

Zn

c)

CuSO4

d)

ZnSO4

12.
If Al is above Co in the activity series of metals, which of the following will occur if Al metal is put into a solution of cobalt nitrate?
a)
a redox reaction takes place
b)
the Al strip dissolves
c)
the Al strip becomes coated with cobalt
d)
all of the above
13.

What occurs to the mass of copper electrode in the following reaction?

Zn/Zn2+ // Cu2+/Cu

a)

increases

b)

decreases

c)

remains the same

14.

Which metal is the negative electrode?

Zn/Zn2+ // Cu2+/Cu

a)

zinc

b)

copper

15.

What would be the theoretical cell potential of the previous electrochemical cell?

Ag+/Ag = 0.80V

Ni2+/Ni = -0.25V

a)

1.05V

b)

-1.05V

c)

0.55V

d)

-0.55V

16.
What unit of measurement do we use to measure electrical potential?
a)
Watts
b)
Volts
c)
Amps
d)
Ohms
17.

EO represents

a)

Single electrode potential

b)

Standard electrode potential

c)

Standard hydrogen electrode

d)

None

18.

In electrochemical cell, oxidation takes place at

a)

Right

b)

Left

c)

Top

d)

Bottom

19.

In electrochemical cell, reduction takes place at

a)

Right

b)

Left

c)

Top

d)

Bottom

20.
If the cell potential is negative, the reaction is?
a)
 a success
b)
spontaneous
c)
not spontaneous
21.

In electrolysis of copper purification, at cathode

a)

pure copper gets deposited

b)

the object to be electroplated is kept

c)

impure copper gets deposited

d)

CuSO4 gets deposited

22.

An electrolytic cell uses electrical energy to drive

a)

chemical reaction

b)

physical reaction

c)

no reaction

d)

none of above

23.
Which of the following is the balanced half -reaction for the oxidation of Cu to Cu+2?
a)
Cu   --> Cu+2
b)
Cu + 2 e-   --> Cu+2
c)
Cu  --> Cu+2  + 2 e-
d)
Cu - 2e-  --> Cu+2
24.
What reaction occurs at the anode?
a)
Ag+ + e- →Ag
b)
Ag → Ag+ + e-
c)
Ni2+ + 2e- → Ni
d)
Ni → Ni2+ + 2e-
25.
What unit of measurement do we use to measure electrical potential?
a)
Watts
b)
Volts
c)
Amps
d)
Ohms