Chapter 20 - Oxidation-Reduction Reactions

Question 0

What’s a half reaction?

Answer 0

It’s an equation showing just the oxidation or just the reduction that takes place in a redox reaction.

Question 1

What are two classes of chemical reactions?

Answer 1

One class of chemical reactions is oxidation-reduction (redox) reactions, in which electrons are transferred from one reactions species to another. The other class includes all other reactions, in which no electron transfer occurs.

Question 2

What do you do in a half reaction method?

Answer 2

You write and balance the oxidation and reduction half-reactions separately before combining them into a balanced redox equation.

Question 3

Practice #19 & #20.

Answer 3

Okay.

Question 4

List the 6 rules for assigning oxidation numbers.

Answer 4

1) The oxidation # of a monatomic ion (Ex: Br) is = ionic charge. (Ex: Br1-)
2) The oxidation # of H in a compound is +1.
3) The oxidation # of O in a compound is -2
4) The oxidation # of an atom in elemental form is 0. (Ex: N2’s charge is 0)
5) For a neutral compound, sum of the oxidation #’s of the atoms must = 0.
6) For a polyatomic ion, sum of the oxidation #’s must = ionic equal of the ion.

Question 5

Define oxidation and reduction in terms of the gain or loss of oxygen.

Answer 5

Oxidation: gains oxygen
Reduction: loses oxygen

Question 6

Define oxidation and reduction in terms of the gain or loss of electrons

Answer 6

OIL RIG
Oxidation is loss of e-
Reduction is gain of e-

Question 7

How do you identify the oxidizing agent and the reducing agent in a redox reaction?

Answer 7

The substance that loses electrons is the REDUCING AGENT.

The substance that accepts electrons is the OXIDIZING AGENT.