Reduction-Oxidation (redox) Reactions

Question 1

What is a redox reaction?

Answer 1

A reaction where electrons are transferred from one particle to another. One particle loses electrons, and the other particle gains electrons. The number of electrons gained must be equal to the amount lost.

Question 2

What is oxidation?

Answer 2

The loss of electrons, will be indicated as an increase in charge (ex +1 –> +3)

Question 3

What is reduction?

Answer 3

The gain of electrons, will be indicated as a decrease in charge (ex 0 –> -1)

Question 4

What are oxidation numbers?

Answer 4

They indicate the number of electrons gained, lost, or shared by an atom when it reacts.

Question 5

What are the rules for determining oxidation numbers?

Answer 5

• the oxidation number for any uncombined element is 0, including diatomic elements (HONClBRIF)
• the oxidation number of any monatomic ion is the charge of the ion. (ex Na^+ oxidation number is 1+)
• the sum of any charges in a compound must be zero.
• the sum of any charges of any polyatomic ion is the net charge of the ion.
• the oxidation number of H is always +1, except for KH, and the oxidation number for O is always -2, except for H202.

Question 6

What is a half reaction?

Answer 6

A redox reaction can be represented by two half reactions. The reduction half reaction and the oxidation half reaction. Half reactions must show BOTH conservation of CHARGE and MASS.