1.7 Oxidation,Reduction and Redox Equations

Question 1

What is an oxidation number?

Answer 1

The number of electrons lost or gained by an atom of an element in a compound

Question 2

What is disproportionation?

Answer 2

When the same element is oxidised and reduced in the same reaction

Question 3

What is the oxidation number of any pure element?

Answer 3

0 because it hasn’t reacted with anything to lose or gain electrons

Question 4

What is the oxidation number on simple ions?

Answer 4

The same as the charge of the ion

Question 5

What must the sum of the oxidation numbers equal?

Answer 5

The overall charge on the species

Question 6

What is the oxidation rule in molecules and more complex ions?

Answer 6

The more electronegative element is the negative one

Question 7

What are some fixed oxidation numbers?

Answer 7

Group 1= +1
Group 2 = +2
Al= +3
O= -2
h=+1
F= -1
Halogens= -1

Question 8

How do you balance equations using oxidation numbers?

Answer 8

1. Work out oxidation numbers
2. Balance atoms that change oxidation number
3. Identify redox pairs
4. Balance so reduction=oxidation
5. Balance oxygen by adding H2O
6. Add H+ to balance H

Question 9

Balancing Redox equations steps?

Answer 9

• Balance atoms
• Balance oxygen using H2O
• Balance hydrogen using H+
• Balance charges