redox reactions

Question 1

What is oxidation

Answer 1

Addition of oxygen
Loss of hydrogen
Loss of electrons

Question 2

What is reduction

Answer 2

Loss of hydrogen
Addition of oxygen
Gain of electrons

Question 3

What is an oxidising agent

Answer 3

Oxidises other species
Accepts electrons
Are themselves reduced

Question 4

What is a reducing agent

Answer 4

Reduce other species
Donate electrons
Are themselves oxidised

Question 5

What is oxidation state of an atom in a compound

Answer 5

The charge that atom would have if the compound consisted of separate ions

Question 6

Rule 1

Answer 6

An element on it’s own has an oxidation state of 0

Question 7

Rule 2

Answer 7

Simple ions have an oxidation state equal to the charge of the ion. E.g.
Na+ has an oxidation state of +1

Question 8

Rule 3

Answer 8

Some oxidation states must be learnt
Hydrogen +1
Oxygen -2
Chlorine and fluorine -1

Question 9

Rule 4

Answer 9

In a compound the sum of the oxidation states is 0

Question 10

Rule 5

Answer 10

For a complex ion, the sum of all the oxidation states equals the charge on the ion
NO3- is -1

Question 11

Expect ions to the rules

Answer 11

Hydrogen: +1 except in compounds with groups 1 or 2
Oxygen: -2 except in peroxides or with fluorine
Chlorine: -1 except when bonded to fluorine or oxygen

Question 12

How does oxidation state change during redox

Answer 12

Increases during oxidation
Decreases during reduction