Making Electricity

Page
3

Electrons given to H ions

H ions gain electrons to form H atoms

Metals above hydrogen in the electrochemical series react with dilute acids to produce hydrogen gas. Metals below hydrogen do not react with dilute acids.

Slide 17

The ion-electron equations (page 7 in data booklet) can be re-written to show each step in the reaction:

Slide 18

Oxidation and Reduction

OIL RIG

oxidation is loss reduction is gain

OF ELECTRONS

Oxidation is a loss of electrons by a reactant in any reaction.

Reduction is a gain of electrons by a reactant in any reaction.

Slide 19

Oxidation and Reduction

REDOX

reduction oxidation

In a redox reaction, reduction and oxidation go on together.

A metal element reacting to form a compound is an example of oxidation.

A compound reacting to form a metal element is an example of reduction.

Slide 20

Oxidation and reduction in complex ion-electron equations (page 7 in data booklet),

e.g. as written in data booklet

SO42-(aq) + 2H+(aq) + 2e --> SO32-(aq) + H2O(l)

this shows reduction (electrons on the reactant side of the arrow).

Reversing this ion-electron equation gives

SO32-(aq) + H2O(l) --> SO42-(aq) + 2H+(aq) + 2e

which shows oxidation (electrons on the product side of the arrow).