Unit C: Electrochemical Changes Module 5

Question 1

Electrochemical reaction

Answer 1

Reaction that involves a transfer of electrons

Question 2

Spectator ion

Answer 2

An ion that doesn’t participate in an chemical reaction

Question 3

Oxidation

Answer 3

Loss of electrons

Entity undergoing oxidation will increase in oxidation number

Question 4

Reduction

Answer 4

Gain of electrons

Entity undergoing reduction will decrease in oxidation number

Question 5

Oxidizing agent

Answer 5

Substance that causes oxidation while undergoing reduction

Question 6

Reducing agent

Answer 6

Substance that causes reduction by undergoing oxidation

Question 7

Disproportionation reaction

Answer 7

When the same substance is both reduced and oxidized at the same time (both RA and OA)

Question 8

Oxidation Number Rules:
Hydrogen
Hydrogen
Oxygen
Oxygen
Alkali Metals
Alkali Earth Metals
Halogens

Answer 8

Hydrogen in most compounds=+1
Hydrogen in hybrides =-1
Oxygen in most compounds=-2
Oxygen in peroxide’s=-1
Alkali metals=+1
Alkali Earth Metals=+2
Halogens in most binary Ionic compounds =-1

Question 9

Evidence of a spontaneous redox reaction

Answer 9

Colour change
pH change
Formation of a precipitate
Formation of gas bubbles
Temp change

Question 10

Electron Transfer Theory

Answer 10

Total number of electrons gained=total number of electrons lost

Question 11

Half Reaction

Answer 11

balanced chemical reaction showing oxidation or reduction