unit 9 vocab

Question 1

oxidation

Answer 1

loss of electrons, oxidation state increases

Question 2

reduction

Answer 2

gain of electrons, oxidation state decreases

Question 3

electrical current

Answer 3

the flow of electric charge

Question 4

electrochemical cell

Answer 4

a device that uses redox reactions to generate electricity or an electrical current to drive a chemical reaction

Question 5

voltaic (galvanic) cell

Answer 5

an electrochemical cell that produces electrical current from a spontaneous chemical reaction

Question 6

electrolytic cell

Answer 6

an electrochemical cell that consumes electrical current to drive a nonspontaneous chemical reaction

Question 7

half-cell

Answer 7

one half of an electrochemical cell where oxidation or reduction occurs

Question 8

electrode

Answer 8

conductive surface where electrons can enter or leave a half-cell in an electrochemical cell

Question 9

amperes (A)

Answer 9

unit for electrical current. one coulomb per second, or 6.242 * 10 ^-8 electrons per second

Question 10

potential difference

Answer 10

measure of the difference in potential energy (in Joules) per unit of charge (in Coulombs)
1V=1J/c

Question 11

electromotive force (emf)

Answer 11

results in the motion of electrons due to a difference in potential

Question 12

cell potential (Ecell or cell emf)

Answer 12

potential difference between 2 electrodes

Question 13

anode

Answer 13

the electrode in an electrochemical cell at which oxidation occurs; electrons flow away from the anode (its the more neg side)

Question 14

cathode

Answer 14

where reduction occurs; electrons flow towards the cathode (it’s the more pos side)

Question 15

salt bridge

Answer 15

inverted u-shape tube with strong electrolyte connecting 2 half-cells, allowing a flow of ions, neutralizing the charge builup

Question 16

standard electrode potential

Answer 16

potential of a half-cell

Question 17

electrode potential of SHE (standard hydrogen electrode)

Answer 17

zero

Question 18

dry-cell battery

Answer 18

doesnt contain a large amount of liquid water, often using the oxidation of Zn and reduction of MNO2 to provide the electrical current

Question 19

alkaline battery

Answer 19

employs half-reactions in a basic medium. has a longer life

Question 20

lead-acid storage battery

Answer 20

used in cars. uses oxidation of Pb and reduction of Pb4 oxide in sulfuric acid to provide electrical current

Question 21

fuel cell

Answer 21

reactants from outside source constantly flow through the battery, generating current

Question 22

electrolysis

Answer 22

electrical current drives an otherwise nonspontaneous redox reaction

Question 23

corrosion

Answer 23

oxidation of metals exposed to oxidizing to oxidizing agents in the environment

Question 24

enthalpy

Answer 24

change in H, involves heat

Question 25

entropy

Answer 25

change in S, involves disorder/chaos :)!!