Chapter 4: 4.1 Redox Reactions

Question 1

What are oxidation-reduction reactions commonly known as? What are they?

Answer 1

“Redox” reactions
Characterized by a change in the oxidation state of one or more elements in the reactants
* When there is a net transfer of electrons from one reactant to another

Question 2

Define:

Oxidation half-reaction

Answer 2

One half-reaction where electrons are lost (donated)

Question 3

Define:

Reduction half-reaction

Answer 3

One half-reaction where electrons are gained (received)

Question 4

Describe the acronym:

OIL RIG

Answer 4

Oxidation Is Loss (OIL)
Reduction Is Gain (RIG)

Question 5

Define:

Reducing agent

Answer 5

In a redox reaction:
* The species that donates (or loses) electrons

Question 6

True or False:

In the redox reaction, the reducing agent is reduced

Answer 6

False, it is oxidized

Question 7

Define:

Oxidizing agent

Answer 7

In a redox reaction:
* The species that accepts (or gains) electrons

Question 8

True or False:

In a redox reaction, the oxidizing agent is reduced

Answer 8

True

Question 9

True or False:

Oxidation and reduction always occur together

Answer 9

True

Question 10

True or False:

The electrons lost in the oxidation half-reaction is more than those gained in the reduction half-reaction

Answer 10

False, the number of electrons lost in the oxidation half-reaction must equal those gained in the reduction half-reaction

Question 11

Define:

Oxidation states

Answer 11

Used to facilitate the electron accounting in redox reactions

Question 12

State:

The rules for assigning Oxidation States

Answer 12

1. In a pure element or elemental substance, oxidation state = 0
2. Specific oxidation states to elements in a compound (separate flashcard)
3. Oxidation state = Charge on a monatomic ion
4. In a neutral species, oxidation state = 0
5. In a complex ion, oxidation state = total charge on ion

Question 13

What are the general rules for oxidation state of elements in a compound?

Answer 13

In the following order:
1. Fluorine is always -1
2. Group 1 metals are +1
3. Group 2 metals are +2
4. Hydrogen is +1 (except when bounded to metal, it is -1)
5. Oxygen is usually -2
6. Other halogens are usually -1

Question 14

List oxidation states of carbon

Answer 14

1. For C-O bonds, contributes +1 to the carbon
2. For C-H bonds, contributes -1 to the carbon
3. For C=O bonds, contributes +2 to the carbon
4. For C-C bonds, contribtues 0 to the carbon

Question 15

Define:

Disproportionation reaction

Answer 15

A substance in an intermediate oxidation state goes to higher and lower states by electron transfer