Deck 13: Electrochemistry

Question 1

Galvanic corrosion may occur only when two different metals are in contact with one another.

Answer 1

True

Question 2

The species undergoing reduction is referred to as the oxidizing agent.

Answer 2

True

Question 3

Copper has a greater tendency to corrode than does zinc.

Answer 3

False

Question 4

Electrolysis involves using an external current to drive an electrochemical reaction in a non-spontaneous direction.

Question 5

All dry cell batteries are rechargeable.

Question 6

In the formation of iron (II) oxide, which species is being reduced?
Fe( s ) + O₂( g ) → FeO( s )

A) FeO
B) Fe₂O₃
C) Fe
D) O₂

Question 7

In the formation of iron (II) oxide, which species is being reduced?
Fe( s ) + O₂( g ) → FeO( s )

A) FeO
B) Fe₂O₃
C) Fe
D) O₂

Question 8

In a redox reaction:

A) there is a transfer of protons from one species to another.
B) electrons are created.
C) electrons are transferred between two species.
D) the reaction always moves in a reverse direction.

Question 9

Reduction occurs at the anode of a Galvanic cell.

Question 10

Which phrase best describes the half-reaction as written?
Na⁺ + e ⁻ → Na

A) oxidation 1/2 reaction
B) reduction 1/2 reaction
C) group 2 ionization
D) two electron transfer

Question 11

The standard hydrogen electrode (SHE) involves gaseous HCl at 1 atm being bubbled into water.

Question 12

The Nernst equation describes the pH required to convert electrolytic reactions into spontaneous Galvanic cells.

Question 13

The kinetics of uniform corrosion will speed up considerably in the presence of good electrical conducting salts such as NaCl

Question 14

A Galvanic cell is an electrochemical cell in which a spontaneous chemical reaction may be used to generate an electrical current.

Question 15

In the decomposition of hydrogen peroxide, which atom is being reduced?
H₂O₂( aq ) → H₂( g ) + O₂( g )

A) H
B) O
C) both
D) neither

Question 16

Secondary cells are designed to be rechargeable.

Question 17

Electrolysis can be used to electroplate metals onto surfaces.

Question 18

The standard state of an electrochemical cell is measured as 1 atm pressure for all gases and 1.0 M for all aqueous solutions.

Question 19

Species with positive standard reduction potentials are excellent candidates for reduction reactions.

Question 20

In balancing electrochemical half-reactions in acidic media, one can assume an excess of both water and OH^-.

Question 21

Using the provided standard reduction potentials, which of the following cells is an example of a Galvanic cell?

A)
B)
C)
D)

Question 22

The formation of thin layers of material on the electrodes of a secondary cell will result in:

A) an increase in the EMF of the battery.
B) formation of explosive hydrates.
C) shorter periods of usefulness between recharging sessions.
D) the creation of j-p junction gaps at the electrode surfaces.

Question 23

What is the oxidation number of Mn in MnO₄ ⁻ ?

A) 1+
B) 2+
C) 7+
D) 8+

Question 24

Balance the following electrochemical reaction in acid:
MnO₄ ⁻ ( aq ) + Zr( s ) ↔ Mn²⁺( aq ) + Zr²⁺( aq )

A) 2 MnO₄ ⁻ ( aq ) + 16H⁺( aq ) + 5 Zr( s ) → 2 Mn²⁺( aq ) + 5 Zr²⁺( aq ) + 8 H₂O( l )
B) 2 MnO₄ ⁻ ( aq ) + 5 Zr( s ) → 2 Mn²⁺( aq ) + 5 Zr²⁺( aq )
C) MnO₄ ⁻ ( aq ) + Zr( s ) → Mn²⁺( aq )+ Zr²⁺( aq ) + 5 e ⁻
D) 2 MnO₄ ⁻ ( aq ) + 8H⁺( aq ) + 5 Zr( s ) → 2 Mn²⁺( aq ) + 5 Zr²⁺( aq ) + 8 H₂O( l )

Question 25

How many grams of silver are deposited at a platinum cathode in the electrolysis of AgNO₃ (aq) by 5.30 amps of electric current in 4.0 hours?

A) 85.3 g
B) 42.6 g
C) 121 g
D) 188 g

Question 26

What is the oxidation number of Cl in HClO₄?

A) 1+
B) 2+
C) 7+
D) 8+

Question 27

Which mechanism is most energy efficient?

A) internal combustion motor
B) a voltaic fuel cell
C) electricity from coal fired plants

Question 28

What is the E⁰ value for the Galvanic cell formed from these two half-reactions?

A) −1 .43 V
B) +1.43 V
C) −0 .93 V
D) +0.93 V

Question 29

How long will it take to collect 1.0 L of H₂ (g) at STP in the electrolysis of 2.0 M HCl with a current of 4.25 A?

A) 15 min
B) 34 min
C) 2.8 hr
D) 11 hr

Question 30

Given a Galvanic cell: , the right-hand side of this notation represents the:

A) spontaneous half of the reaction.
B) oxidation 1/2 reaction.
C) anode of the cell.
D) reduction 1/2 reaction.

Question 31

What is the E value for the Galvanic cell formed from these two half-reactions at these concentrations?

A) 1.90 V
B) 1.95 V
C) 1.99 V
D) 2.20 V

Question 32

An oxidation occurs at the ____ of a Galvanic cell.

A) intersection
B) anode
C) p-n junction
D) cathode

Question 33

The salt bridge between 1/2 reactions maintains the electrical balance of a Galvanic cell. This bridge is filled with:

A) strong electrolytes.
B) inert carbon.
C) weak electrolytes.
D) interstitial membranes.

Question 34

What is the E value for the Galvanic cell formed from these two half-reactions at these concentrations?

A) 1.00 V
B) 1.12 V
C) 1.24 V
D) 0.36 V

Question 35

The SHE is assigned a voltage of ____ V.

A) − 1.000
B) 1.000
C) 0.150
D) 0.000

Question 36

What is the E⁰ value for the Galvanic cell formed from these two half-reactions?

A) +1.334 V
B) − 2.046 V
C) +2.046 V
D) +2.758 V

Question 37

Single use, non-rechargeable batteries are referred to as:

A) primary cells
B) secondary cells
C) tertiary cells
D) electrolytic cells

Question 38

What is the E⁰ value for the Galvanic cell formed from these two half-reactions?

A) − 2.31 V
B) +4.33 V
C) − 1.32 V
D) +2.00 V

Question 39

Identify the correct balanced chemical equation for the cell:

A) Al( s ) + Hg²⁺( aq ) → Al³⁺( aq ) + Hg( l )
B) 2 Al( s ) + Hg²⁺( aq ) → 2 Al³⁺( aq ) + Hg( l )
C) Al( s ) + 3 Hg²⁺( aq ) → Al³⁺( aq ) + 3 Hg( l )
D) 2 Al( s ) + 3 Hg²⁺( aq ) → 2 Al³⁺( aq ) + 3 Hg( l )

Question 40

The rusting witnessed in the sheet metal of a '65 Impala is an example of:

A) uniform corrosion.
B) galvanic corrosion.
C) electrolysis.
D) compounding corrosion.