1) the Gain of Electrons by an Element Is Called ______

CFA -Electrochem

1) The gain of electrons by an element is called ______.

A) reduction

B) oxidation

C) disproportionation

D) fractionation

E) sublimation

2) Which substance is oxidized in the reaction below?

A) Pb

B)

C)

D)

E)

3) What is the oxidation number of potassium in ?

A) 0

B) +1

C) +2

D) -1

E) +3

4) The balanced half-reaction in which dichromate ion is reduced to chromium(III) ion is a ______process.

A) four-electron

B) twelve-electron

C) three-electron

D) six-electron

E) two-electron

5) The electrode at which oxidation occurs is called the ______.

A) oxidizing agent

B) cathode

C) reducing agent

D) anode

E) voltaic cell

6) The standard cell potential for the voltaic cell based on the reaction below is ______V.

A) +0.30

B) +2.80

C) +3.10

D) +0.83

E) -0.16

7) The relationship between the change in Gibbs free energy and the emf of an electrochemical cell is given by ______.

A)

B)

C) ΔG = -nFE

D) ΔG = -nRTF

E)

8)The standard cell potential for the reaction below is +0.63 V. The cell potential for this reaction is ______V when and

A) 0.52

B) 0.85

C) 0.41

D) 0.74

E) 0.63

9) How many grams of Cu are obtained by passing a current of 12 A through a solution of for 15 minutes?

A) 0.016

B) 3.6

C) 7.1

D) 14

E) 1.8

Short Answer

10) In the formula ΔG = -nFE , F is the ______.

11) The dependence of cell emf on concentration is expressed in the ______equation.

12) The quantity of charge passing a point in a circuit in one second when the current is one ampere is called a ______.

Questions 13-15 refer to galvanic cells made from different combinations of the three half-cells described below.

Half-cell 1: strip of Al(s) in 1.00 M Al(NO3)3(aq)

Half-cell 2: strip of Cu(s) in 1.00 M Cu(NO3)2(aq)

Half-cell 3: strip of Fe(s) in 1.00 M Fe(NO3)2(aq)

Galvanic cell Half-cells Cell reaction Ecello( V)

X 1 and 2 2 Al(s) + 3 Cu2+(aq) à 2 Al3+(aq) + 3 Cu(s) 2.00

Y 1 and 3 2 Al(s) + 3 Fe2+(aq) à 2 Al3+(aq) + 3 Fe(s) 1.22

Z 2 and 3 Fe(s) + Cu2+(aq) à Fe2+(aq) + Cu(s) ?

13. What is the standard cell potential of galvanic cell Z?

a. 0.26 V

b. 0.78 V

c. 2.34 V

d. 3.22 V

14. In galvanic cells Y and Z, which of the following takes place in half cell 3?

a. Reduction occurs in both cell Y and cell Z.

b. Oxidation occurs in both cell Y and cell Z.

c. Reduction occurs in cell Y, and oxidation occurs in cell Z

d. Oxidation occurs in cell Y, and reduction occurs in cell Z.

15. If the half cell containing 1.00 M Fe(NO3)2(aq) in galvanic cells Y and Z is replaced with a half cell containing 5.00 M Fe(NO3)2(aq), what will be the effect on the cell voltage of the two galvanic cells?

a. The voltage will increase in both cells.

b. The voltage will decrease in both cells.

c. The voltage will increase in cell Y and decrease in cell Z.

d. The voltage will decrease in cell Y and increase in cell Z.