Book: Key Terms: Ch. 21

Question 1

anode

Answer 1

The electrode at which oxidation occurs in an electrochemical cell. Electrons are given up by the reducing agent and leave the cell at the anode.

Question 2

ampere (A)

Answer 2

The SI unit of electric current; 1 ampere of current results when 1 coulomb of charge flows through a conductor in 1 second.

Question 3

battery

Answer 3

A group of voltaic cells arranged in series; primary and secondary types are self-contained, but flow batteries are not.

Question 4

cathode

Answer 4

The electrode at which reduction occurs in an electrochemical cell. Electrons enter the cell and are acquired by the oxidizing agent at the cathode.

Question 5

cell potential (E_cell)

Answer 5

aka electromotive force, or emf; cell voltage. The difference in electrical potential between the two electrodes of an electrochemical cell.

Question 6

concentration cell

Answer 6

A voltaic cell in which both compartments contain the same components but at different concentrations.

Question 7

coulomb (C)

Answer 7

The SI unit of electric charge. One coulomb is the charge of 6.242×10^18 electrons; one electron possesses a charge of 1.602×10^-19 C.

Question 8

corrosion

Answer 8

The natural redox process that results in unwanted oxidation of a metal.

Question 9

electrochemical cell

Answer 9

A system that incorporates a redox reaction to produce or use electrical energy.

Question 10

electrochemistry

Answer 10

The study of the relationship between chemical change and electrical work.

Question 11

electrolytic cell

Answer 11

An electrochemical system that uses electrical energy to drive a nonspontaneous chemical reaction (∆G > 0).

Question 12

electrode

Answer 12

The part of an electrochemical cell that conducts the electricity between the cell and the surroundings.

Question 13

electrolyte

Answer 13

A substance that conducts a current when it dissolves in water. A mixture of ions, in which the electrodes of an electrochemical cell are immersed, that conducts a current.

Question 14

electromotive force (emf)

Answer 14

aka cell potential. The difference in electrical potential between the two electrodes of an electrochemical cell.

Question 15

electrolysis

Answer 15

The nonspontaneous lysing (splitting) of a substance, often to its component elements, by the input of electrical energy.

Question 16

Faraday constant (F)

Answer 16

The physical constant representing the charge of 1 mol of electrons: F = 96485 C / mol e⁻

Question 17

fuel cell

Answer 17

aka flow battery. A battery that is not self-contained and in which electricity is generated by the controlled oxidation of fuel.

Question 18

half-cell

Answer 18

A portion of an electrochemical cell in which a half-reaction takes place.

Question 19

half-reaction method

Answer 19

A method of balancing redox reactions by treating the oxidation and reduction half-reactions separately.

Question 20

Nernst equation

Answer 20

An equation stating that the voltage of an electrochemical cell under any conditions depends on the standard cell voltage and concentrations of the cell components: E_cell = Eº_cell - ( RT / nF ) ln( Q )

Question 21

overvoltage

Answer 21

The additional voltage, usually associated with gaseous products forming at an electrode, that is required above the standard cell voltage to accomplish electrolysis.

Question 22

salt bridge

Answer 22

An inverted U tube containing a solution of nonreacting ions that connects the compartments of a voltaic cell and maintains neutrality by allowing ions to flow between the compartments.

Question 23

standard cell potential (Eº_cell)

Answer 23

The potential of a cell measured with all components in their standard states and no current flowing.

Question 24

standard electrode (half-cell) potential (Eº_half-cell)

Answer 24

aka standard half-cell potential. The standard potential of a half-cell, with the half-reaction written as a reduction.

Question 25

standard reference half-cell (standard hydrogen electrode)

Answer 25

aka standard hydrogen electrode. A specially prepared platinum electrode immersed in 1 M H+ (aq) through which H2 gas at 1 atm is bubbled. Eº_half-cell is defined as 0 V.

Question 26

volt (V)

Answer 26

The SI unit of electric potential: 1 V = 1 J / C.

Question 27

voltaic (galvanic) cell

Answer 27

an electrochemical cell that uses a spontaneous redox reaction to generate electrical energy.

Question 28

voltage

Answer 28

aka cell potential. The difference in electrical potential between the two electrodes of an electrochemical cell.