biological oxidation -4

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Transfer of Electrons

1

An oxidation–reduction reaction transfers electrons from one reactant to

another

Oxidation Is a Loss of electrons (OIL)

Zn(s) Zn2+(aq) + 2e

Reduction Is a Gain of electrons (RIG)Cu2+(aq) + 2e Cu(s)


Oxidation and Reduction

2


Oxidized or Reduced?

3


Zn and Cu2+

4

oxidationZn(s) Zn2+(aq) + 2e-Silvery metal

reduction Cu2+(aq) + 2e- Cu(s)


Electron Transfer from Zn to Cu2+

Oxidation: electron loss

Reduction: electron gain

5


Learning Check

6

Identify each of the following as:1) oxidation or 2) reduction

__A. Sn(s) Sn4+(aq) + 4e−

__B. Fe3+(aq) + 1e− Fe2+(aq)

__C. Cl2(g) + 2e− 2Cl−(aq)


Solution

7

Identify each of the following as:1) oxidation or 2) reduction

1 A. Sn(s) Sn4+(aq) + 4e−

2 B. Fe3+(aq) + 1e− Fe2+(aq)

2 C. Cl2(g) + 2e− 2Cl−(aq)


Writing Oxidation and Reduction Reactions

8

Write the separate oxidation and reduction reactions for the following equation.

2Cs(s) + F2(g) 2CsF(s)

Each cesium atom loses an electron to form a cesium ion.

2Cs(s) 2Cs+(s) + 2e− oxidation

Each fluorine atom gains an electron to form a fluoride ion.

F2(s) + 2e– 2F−(s) reduction


Learning Check

9

In light-sensitive sunglasses, UV light initiates an

oxidation–reduction reaction. uv light

Ag+ + Cl− Ag + Cl

A. Which reactant is oxidized?

B. Which reactant is reduced?


Solution

10

In light-sensitive sunglasses, UV light initiates an oxidation-reduction reaction. uv light

Ag+ + Cl− Ag + Cl

A. Which reactant is oxidized? Cl − Cl− Cl + 1e−

B. Which reactant is reduced? Ag+ Ag+ + 1e− Ag


Learning Check

11

Identify the substances that are oxidized and reduced in

each of the following reactions:A. Mg(s) + 2H+(aq) Mg2+(aq) + H2(g)

B. 2Al(s) + 3Br2(g) 2AlBr3(s)


Solution

12

Identify the substances that are oxidized and reduced in

each of the following reactions:A. Mg is oxidized Mg(s) Mg2+

(aq) + 2e−

H+ is reduced 2H+ + 2e− H2

B. Al is oxidized 2Al 2Al3+ + 6e−

Br is reduced 2Br + 2e− 2Br−


Oxidation–Reduction in Biological Systems

13

In biological systems, oxidation may involve the loss of H the gain of O

In biological systems, reduction may involve the gain of H the loss of O


Oxidation–Reduction in Biological Systems (continued)

14


Summary of Oxidation and Reduction

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biological oxidation -4

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