3.1.7 Oxidation, Redox, Reduction Reactions

Question 1

Reducing agent

Answer 1

Lose electrons so they oxidise themselves

Question 2

Oxidising agent

Answer 2

Gain electrons so they reduce themselves

Question 3

Oxidation number of elements E.g. Cl2

Answer 3

0

Question 4

Oxidation number of ions

Answer 4

Same as charge

Question 5

Group 1 oxidation number

Answer 5

+1

Question 6

Group 2 oxidation number

Answer 6

+2

Question 7

Aluminium oxidation number

Answer 7

+3

Question 8

Hydrogen oxidation number

Answer 8

+1
Except in hydrides it’s -1 E.g. NaH

Question 9

What is a hydride

Answer 9

When hydrogen is bonded to a metal

Question 10

Chlorine oxidation number

Answer 10

-1
Except in compounds with F and O E.g. ClF3 it’s Cl+3

Question 11

Fluorine oxidation number

Answer 11

-1

Question 12

Oxygen oxidation number

Answer 12

-2
Except in peroxides it’s -1
Except in OF2 it’s +2

Question 13

When giving oxidation numbers what would H2O2 the oxidation state of oxygen be

Answer 13

-1
1) because peroxide
2) only given oxidation state of 1 oxygen not 2

Question 14

How do you find oxidation state if molecule has a charge

Answer 14

The charges don’t add to 0 they add up to the charge on the molecule

Question 15

Reduction is an increase/decrease in oxidation number

Answer 15

Decrease

Question 16

Oxidation is an increase/decrease in oxidation number

Answer 16

Increase

Question 17

Do you use big numbers in oxidation states

Answer 17

No

Question 18

Steps on how to balance half equations

Answer 18

1) Write down what you have before and after
2) balance any atoms apart from oxygen and hydrogen
3) balance oxygens with water
4) balance hydrogens with H+ ions
5) balance charges with electrons

Question 19

Example of 3 common peroxides

Answer 19

H2O2
BaO2
Na2O2

Question 20

Do use use big numbers when finding charges when backing ionic equation

Answer 20

YES

Question 21

What to do when combing half equations

Answer 21

Make electrons equal E.g. multiple one of the whole equation
Combine electrons should cancel
NO ELECTRONS IN FINAL EQUATION