New World American Private School
Worksheet 1
Topic :Electrochemistry
Name:
Date
Subject: Chemistry Grade: 12
Question 1 : Identify the following reactions as oxidation and reduction reactions
1.
k→ k+
2.
s→s-2
3.
F-→F2
4.
Fe+3→Fe+2
5.
Na →Na+
Question 2 : For each one of the above reactions ,write the electronic equation indicating the
corresponding number of electrons lost or gained
1.
2.
3.
4.
5.
Question 2 : Circle the correct answer:
1. In an electrochemical cell, electrons are generated at the
a. anode.
b. cathode.
c. circuit.
d. electrolyte.
2. What is used to keep two half-cells apart but allow charges to flow?
a. an electrolyte
b. a cathode
c . a porous barrier
d. an anode
3. Where does oxidation take place in an electrochemical cell?
a. the anode
b. the cathode
c. the anode or the cathode d. the half-cell
4. The oxidation number of the substance taking part in the reaction that occurs at the cathode
a. decreases.
b. increases.
c. does not change.
d. None of the above
Section: A/D
5. In an electrochemical cell, the cathode is the
a. neutral electrode.
b. electrode at which matter can lose electrons.
c. electrode at which matter gains electrons.
d. electrode at which matter loses electrons.
6. For an electric current to exist in an electrochemical cell, the two half-cells must be
a. connected to a dry cell.
b. in the same solution.
c. completely isolated from one another.
d. connected by a wire and a porous barrier.
7. What is the cell notation for the following net reaction?
Zn(s) + Cu2+(aq) →Zn2+(aq) + Cu(s)
a. Zn(s)|Cu2+(aq)||Zn2+(aq)|Cu(s)
b. Zn(s)|Zn2+(aq)||Cu2+(aq)|Cu(s)
c. Zn2+(aq)|Zn(s)||Cu2+(aq)|Cu(s)
d. Zn(s)|Cu(s)||Zn2+(aq)|Cu2+(aq)
8. If the reactants in an electrochemical cell are in contact,
a. most of the energy is released as an electric current.
b. hydrogen gas is released.
c. oxidation and reduction do not occur.
d. most of the energy is released as heat.
9. In the electrochemical cell shown above, in which direction will positive ions flow?
a. from B to A
b. from A to B
c. from the anode to D
d. from the cathode to D
10. Consider the following cell notation: Mg(s)|Mg2+(aq)||Cu2+(aq)|Cu(s) What is the halfreaction at the anode?
a. Cu2+(aq) + 2e– → Cu(s)
b. Cu(s)→Cu2+(aq) + 2e–
c. Mg2+(aq) + 2e– → Mg(s)
d. Mg(s) → Mg2+ (aq) + 2e–
Q3: Why is it important to have a salt bridge in the electrochemical cell?
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Question 2 : For each one of the above reactions ,write the electronic equation indicating the
corresponding number of electrons lost or gained
1.OXI : K→ K+ +E
2.RED
S+ 2e→S-2
3.OXID 2F- →F2+2e
4.RED Fe+3+E→Fe+2
5.oxi Na →Na+ + e
1. a
2. c
3. a
4. a
5. c
6. d
7. b
8. d
9. b
10. d
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