Acids and Alkalis

Question 1

Name three common household acids:

Answer 1

Vinegar, lemon juice, car battery.

Question 2

Name three common household alkalis:

Answer 2

Soap, drain cleaner, baking powder.

Question 3

State a hazard of strong acids and alkalis

Answer 3

They are corrosive

Question 4

What is an indicator?

Answer 4

A chemical that changes colour in an acid and alkali.

Question 5

Give 3 examples of indicators

Answer 5

Red cabbage indicator; litmus paper; universal indicator

Question 6

What does the pH scale tell us about acids and alkalis?

Answer 6

How strong an acid or alkali is.

Question 7

Name the chemical used to identify the pH of a substance:

Answer 7

Universal indicator

Question 8

What is the colour of a universal indicator in a neutral substance?

Answer 8

Green

Question 9

What is the pH of a neutral substance?

Answer 9

pH 7

Question 10

Give an example of a neutral substance:

Answer 10

Water, blood, salt

Question 11

What is the colour of the universal indicator in a strong acid?

Answer 11

Red

Question 12

What is the pH of a strong acid?

Answer 12

1-3

Question 13

Give an example of a strong acid:

Answer 13

Car battery acid; hydrochloric acid

Question 14

What is the pH of a weak acid?

Answer 14

4-6

Question 15

Give an example of a weak acid:

Answer 15

Vinegar; tomato juice; citric acid in lemon juice; coffee

Question 16

State the colour of strong alkalis on the pH scale?

Answer 16

Purple

Question 17

What is the pH of a strong alkali?

Answer 17

11-14

Question 18

Give an example of a strong alkali:

Answer 18

Bleach, drain cleaner

Question 19

What is the pH of a weak alkali?

Answer 19

8-10

Question 20

Give an example of a weak alkali:

Answer 20

Soap, baking powder

Question 21

What is a neutralisation reaction?

Answer 21

When an acid and an alkali react together.

Question 22

What are the products of a neutralisation reaction?

Answer 22

Salt and water

Question 23

Write the general word equation for a neutralisation reaction:

Answer 23

Acid + alkali 🡪 salt + water

Question 24

What type of salt is produced when an alkali reacts with:

a) Hydrochloric acid
b) Nitric acid
c) Sulphuric acid

Answer 24

a) Metal chloride
b) Metal nitrate
c) Metal sulphate

Question 25

Describe 3 examples of everyday neutralisation reactions:

Answer 25

1. Brushing your teeth using toothpaste to neutralise mouth after eating acidic foods.
2. Farmers use lime to neutralise acidic soil.
3. Indigestion tablets containing alkalis are used to neutralise stomach acid.

Question 26

Sodium Hydroxide + Hydrochloric acid

Answer 26

Sodium Chloride + Water

Question 27

Potassium Hydroxide + Nitric acid

Answer 27

Potassium Nitrate + Water

Question 28

Lithium Hydroxide + Sulphuric acid

Answer 28

Lithium Sulphate + Water

Question 29

A sample of pure salt can be made by reacting copper oxide with sulphuric acid. Complete the word equation:

Copper Oxide + Sulphuric acid

Answer 29

Copper Sulphate + Water

Question 30

Explain why it is important to stir the copper oxide with the sulphuric acid as it is added when making a sample of dry crystals:

Answer 30

Allows the copper oxide to react with the sulphuric acid.

Question 31

Name the technique shown in the diagram below and explain why it is important when making a sample of dry crystals:

Answer 31

Filtration: allows any unreacted copper oxide to be removed.

Question 32

Name the technique shown in the diagram below and explain why it is important when making a sample of dry crystals:

Answer 32

Evaporation: allows the water to be evaporated off, leaving behind the salt.