REDOX

Question 1

Define oxidisation

Answer 1

The process of electron loss

Question 2

Define reduction

Answer 2

The process of electron gain

Question 3

Outline the rules for assigning oxidation numbers

Answer 3

1. All uncombined elements have an oxidation number of 0
2. The oxidation numbers of the elements in a compound add up to 0
3. The oxidation number of a monoatomic ion is equal to its ionic charge
4. The sum of the individual oxidation numbers of the individual elements in a polyatomic ion add to the charge of the ion

Question 4

What are the oxidation numbers of the common compunds

Answer 4

G1 = +1
G2 = +2
Al = +3
H = +1 (except in hydrides -1)
F = -1
Cl, Br = -1 (except in oxygen and fluorine compounds)
O = -2 (except peroxides -1 and fluorine compounds)

Question 5

Define reducing agent

Answer 5

the species that causes another element to reduce and oxidises itself by donating electrons

Question 6

Define oxidising agent

Answer 6

the species that causes another element to oxidise and reduces itself by accepting electrons

Question 7

What are the steps for writing half equations?

Answer 7

1. Work out the oxidation numbers
2. Add electrons equal to the change in oxidation numbers
3. Check to see that the sum of the charges equal on both sides of the reaction

Question 8

What are the extra steps included in writing a half equation when there is a varying amount of O

Answer 8

1. Add H2O to balance out the oxygens

2. Add H+ ions to balance out the H