Ch 20: Oxidation-Reduction Reactions

Question 1

The substance gaining oxygen is ________, while the substance losing oxygen is _______.

Answer 1

oxidized

reduced

Question 2

Loss of electrons is…

Answer 2

Oxidation

Question 3

Where does oxidation take place?

Answer 3

Anode

Question 4

Gain of electrons is…

Answer 4

Reduction

Question 5

Where does reduction take place?

Answer 5

Cathode

Question 6

_________ flow from anode to cathode.

Answer 6

Electrons

Question 7

An __, Red ___

Answer 7

Ox

Cat

Question 8

__ Ox, ___ Cat

Answer 8

An

Red

Question 9

_IL _IG

Answer 9

OIL RIG

Question 10

Oxidation and reduction happen…

Answer 10

together.

Question 11

How the ions travel between cells to keep the charge balanced is…

Answer 11

the salt bridge.

Question 12

Depends on reactivity and more reactive substances have more potential is…

Answer 12

Cell potential (volts)

Question 13

______ electrons is oxidation. _______ electrons is reduction.

Answer 13

Losing

Gaining

Question 14

Iron, a common construction metal often used in the form of the _____ steel, corrodes by being ________ to ions of iron by oxygen.

Answer 14

alloy

oxidized

Question 15

As a general rule, a bonded atom’s _________ ______ is a charge that it would have if the electrons in the bond were assigned to the atom of the more electronegative element.

Answer 15

oxidation number

Question 16

The oxidation number of a monatomic ion is equal in magnitude and sign to its _____ charge.

Answer 16

ionic

Question 17

Rule: ions =

Answer 17

to charge

Question 18

The oxidation number of hydrogen in a compound is…

Answer 18

+1

Question 19

Rule: hydrogen in compounds =

Answer 19

+1

Question 20

Rule: oxygen in compounds =

Answer 20

-2

Question 21

Rule: elements =

Answer 21

0

Question 22

Rule: sum =

Answer 22

to charge

Question 23

An increase in the oxidation number of an atom or ion indicates _________. A decrease in the oxidation number of an atom or ion indicates ________.

Answer 23

oxidation

reduction

Question 24

If the oxidation number of an element in a reacting species changes, then that element has undergone either oxidation or reduction. Therefore, the reaction as a whole must be a _____ reaction.

Answer 24

redox

Question 25

In a balanced redox equation, the total increase in oxidation number of the species oxidized must be balanced by the total ________ in the oxidation number of the species _______.

Answer 25

decrease

reduced

Question 26

To balance a redox equation using half-rections, write separate half-reaction for the oxidation and the reduction. After you balance atoms in each half-reaction, balance _________ gained in the reduction with electrons lost in the oxidation.

Answer 26

electrons

Question 27

Electrochemical cells

Answer 27

Batteries

Question 28

Electrolysis

Answer 28

Battery rechargers

Question 29

Change chemical energy into electrical energy.

Answer 29

Electrochemical cells

Question 30

Change electrical energy into chemical energy.

Answer 30

Electrolysis