Oxidation, Reduction and Redox Reactions

Question 1

What is oxidation?

Answer 1

1. Loss of electrons
2. Loss of hydrogen
3. Gain of hydrogen

Question 2

What is Reduction?

Answer 2

1. Gain of electrons
2. Gain of hydrogen
3. Loss of oxygen

Question 3

What is the oxidation state of an atom?

Answer 3

The charge that would exist on an individual atom if the bonding were completely ionic

Question 4

What are oxidation states used for?

Answer 4

1. To tell if oxidation or reduction has taken place
2. To work out what has been oxidised and/or reduced
3. To construct half equations and balance redox equations

Question 5

What is an oxidising agent?

Answer 5

A substance that oxidises another atom or ion by causing it to lose electrons
It gets reduced itself as it is gaining electrons so oxidation number decreases

Question 6

What is a reducing agent?

Answer 6

A substance that reduces another atom or ion by causing it to gain electrons
It gets oxidised itself as it loses electrons and so oxidation number increases

Question 7

When can a reaction be a Redox reaction?

Answer 7

When there are both oxidising and reducing agents present
Some substances can act as both

Question 8

Why do some elements have roman numerals?

Answer 8

Used to show the oxidation states of transition metals which can have more than one oxidation states

Eg. Iron
Fe3+ written as iron(III) oxide
Fe2+ written as iron(II) oxide