Oxidation states and redox reactions

Question 1

What is oxidation?

Answer 1

the loss of 1 or more electrons

Question 2

What is reduction?

Answer 2

the gain of 1 or more electrons

Question 3

What is a redox reaction?

Answer 3

a reaction that has oxidation and reduction taking place

Question 4

What are the oxidation state rules?

Answer 4

1. all elements in their elemental state have an oxidation state of 0
2. simple ions (involving 1 atom) have an oxidation state of the charge on the ion
3. the sum of oxidation states of all atoms in a neutral molecule is 0
4. the sum of oxidation states in an ion is the charge on the ion
5. hydrogen has an oxidation state of +1 except in metal hydrides (-1)
6. oxygen has an oxidation state of -2 expect in peroxides (-1)
7. some elements can have more than 1 oxidation state - roman numerals are used to indicate the oxidation no

Question 5

What happens to the oxidation state when an element is oxidised?

Answer 5

oxidation state increases

Question 6

What happens to the oxidation state when an element is reduced?

Answer 6

decreases

Question 7

What is the oxidising agent?

Answer 7

the substance that contains the element that is reduced - causes other reacting substances to be oxidised

Question 8

What is the reducing agent?

Answer 8

the substance that contains the element that is oxidised - causes other reacting elements to be reduced