Redox reactions

Question 1

What happens when a strong acid dissolves in water?

Answer 1

Every acid molecule dissociates and releases a hydrogen ion

Question 2

What happens when a weak acid dissolves in water?

Answer 2

A small percentage of the acid molecules dissociates

Question 3

Give examples of strong and weak acids

Answer 3

Strong= H2S04 HNO3 HCL
Weak= CH3COOH

Question 4

Give examples of bases

Answer 4

Metal oxides, metal hydroxides, metal carbonates and ammonia

Question 5

What makes a chemical a base?

Answer 5

Its ability to neutralise an acid to produce a salt

Question 6

Whats an alkali?

Answer 6

Bases that dissolve in water

Question 7

Which group of metals is soluble in water and can form alkalis?

Answer 7

Group 1

Question 8

Alkali + acid?

Answer 8

Salt and water

Question 9

What is the oxidising agent in a redox reaction?

Answer 9

The chemical that accepts the electrons, causing something else to be oxidised

Question 10

What is the reducing agent in a redox reaction?

Answer 10

The chemical that donates the electrons, causing something else to be reduced

Question 11

Give the key point about each of the agents in the reaction

Answer 11

The oxidising agent is reduced and the reducing agent is oxidised

Question 12

Describe all the oxidation rules

Answer 12

Pure elements have atoms with oxidation numbers of zero,
The oxidation state of F is always -1, oxidation state of O is always -2 , -1 in peroxides and +2 when reacted with F. Cl, Br and I have -1 but can have a positive oxidation number when reacted with F or O . H always has oxidation state +1 apart from -1 in hydrides
Group 1 is always plus 1, group 2 is always plus 2 , aluminium is always plus 3 and transition metals is variable.

Question 13

Give the steps in writing a half equation

Answer 13

• Balance for atoms that are not O or H
  -Balance for 0 by adding H2O
  -Balance for H by adding H+ ions
  -Balance charge by adding e
  In order