14.2

Question 1

What are galvanic cells or voltaic cells?

Answer 1

Electric cells adapted for scientific study

Question 2

How do electrons move in a voltaic cell?

Answer 2

Electrons move from the reducing agent to the oxidizing agent through an external circuit rather than directly to each other

Question 3

What does a porous boundary do?

Answer 3

Separates the two electrolytes while permitting ions to move between the two solutions through tiny openings in the cotton plugs of the salt bridge

Question 4

What can each part of a cell be split into?

Answer 4

A half cell

Question 5

What does a half cell consist of?

Answer 5

One electrode and one electrolyte

Question 6

What is a voltaic cell?

Answer 6

An arrangement of 2 half cells separated by a porous boundary

Question 7

What happens to the strongest oxidizing agent in a voltaic cell?

Answer 7

It undergoes reduction at the cathode

Question 8

What happens to the strongest reducing agent in a voltaic cell?

Answer 8

They give up electrons in an oxidation half reaction and enter the solution at the anode

Question 9

What is the cathode in relation to oxidation and reduction?

Answer 9

The cathode is the electrode where the reduction occurs

Question 10

What is the anode in relation to oxidation and reduction?

Answer 10

The anode is the electrode where the oxidation occurs

Question 11

What do inert electrodes do?

Answer 11

Provide a location to connect a wire and a surface on which a half reaction can occur

Question 12

What is standard cell potential?

Answer 12

The maximum electric potential difference (voltage) of the cell operating under standard conditions

Question 13

What is a standard cell?

Answer 13

A voltaic cell in which each half-cell contains all entities shown in the half reaction equation at SATP conditions

Question 14

What is standard reduction potential?

Answer 14

The ability of a standard half cell to attract electrons, thus undergoing reduction

Question 15

Which half-cell gains the electrons?

Answer 15

The half cell with the greater attraction for electrons (the one with the more positive reduction potential)

Question 16

How can standard cell potential be calculated?

Answer 16

Ecell = Er (cathode) - Er (anode)

Question 17

Why is it impossible to determine the reduction potential of a single half cell?

Answer 17

Because electron transfer requires both an oxidizing agent and a reducing agent

Question 18

What is a reference half-cell?

Answer 18

A half-cell that is chosen as a reference and arbitrarily assigned an electrode potential of zero volts (hydrogen)

Question 19

What does the standard hydrogen half-cell consist of?

Answer 19

An inert platinum electrode immersed in hydrogen ions with hydrogen gas bubbling over the electrode

Question 20

What is the reduction potential of hydrogen?

Answer 20

0.00 Volts

Question 21

What does it mean when a reduction potential has a positive value?

Answer 21

The oxidizing agent agen is the stronger agent than hydrogen ions are

Question 22

What does a negative reduction potential mean?

Answer 22

That the oxidizing agent is weaker oxidizing agent than hydrogen ions

Question 23

What cell potential indicates that a reaction is spontaneous?

Answer 23

A cell potential greater than 0

Question 24

What happens as a cell is used continuously for a long time?

Answer 24

The electrical potential difference decreases as the cell operates. Eventually the voltage becomes zero

Question 25

What is corrosion?

Answer 25

An electrochemical process in which a metal reacts with substances in the environment

Question 26

What happens as a metal is oxidized?

Answer 26

Metal atoms lose electrons

Question 27

What accelerates rusting?

Answer 27

Electrolytes. This is why boats rust more easily in saltwater

Question 28

What is the rusting of iron accelerated by?

Answer 28

Acidic solutions, electrolytes, mechanical stresses, and contact with less active metals

Question 29

What are the 2 methods for preventing corrosion?

Answer 29

Protective coating and Cathodic protection

Question 30

Why can paint be a bad protective coating?

Answer 30

Because it only works if the surface is completely covered and the coating remains intact. If a chip occurs then corrosion begins

Question 31

What happens if a crack occurs in a tin protective coating?

Answer 31

Moisture can collect in the crack and an electric cell with tin iron electrodes is created and iron becomes the anode

Question 32

What does zinc plating of steel or iron do?

Answer 32

Provides a double protection of protective layer and preferential corrosion of zinc

Question 33

How does cathodic protection work?

Answer 33

Iron is forced to become the cathode by supplying it with electrons using an impresses current or sacrificial anode

Question 34

What is an impresses current?

Answer 34

An electric current forced to flow toward an iron object by an external potential difference. Prevents corrosion and requires a constant power supply

Question 35

What is using a sacrificial anode?

Answer 35

A sacrificial anode is a metal more easily oxidized that iron connected to the iron object so that it loses its electrons

Question 36

How does zinc playing work?

Answer 36

Zinc anodes are connected to the exposed underwater metal surfaces to prevent of the iron and steel