Separating Mixures

Question 1

Front

Answer 1

Back

Question 2

What is an acid?

Answer 2

A substance with a pH less than 7.

Question 3

What is an alkali?

Answer 3

A substance with a pH greater than 7.

Question 4

What is a neutral substance?

Answer 4

A substance with a pH of 7.

Question 5

What does pH measure?

Answer 5

How acidic or alkaline a substance is.

Question 6

What is the pH range of acids?

Answer 6

pH 0 to 6.

Question 7

What is the pH range of alkalis?

Answer 7

pH 8 to 14.

Question 8

What is the pH of pure water?

Answer 8

pH 7.

Question 9

What colour does universal indicator turn in acid?

Answer 9

Red, orange, or yellow.

Question 10

What colour does universal indicator turn in alkali?

Answer 10

Blue or purple.

Question 11

What colour does universal indicator turn in a neutral substance?

Answer 11

Green.

Question 12

Name a common acid found in citrus fruits.

Answer 12

Citric acid.

Question 13

Which acid is found in vinegar?

Answer 13

Acetic acid (ethanoic acid).

Question 14

Which acid is found in fizzy drinks?

Answer 14

Carbonic acid.

Question 15

Which acid is found in the stomach?

Answer 15

Hydrochloric acid.

Question 16

What does acid in the stomach do?

Answer 16

Helps digestion and kills bacteria.

Question 17

Is lemon juice an acid or alkali?

Answer 17

Acid.

Question 18

Is bleach an acid or an alkali?

Answer 18

Alkali.

Question 19

Is soap an acid or an alkali?

Answer 19

Alkali.

Question 20

What acid is in car batteries?

Answer 20

Sulfuric acid.

Question 21

Which acid is used in fizzy sweets?

Answer 21

Citric or malic acid.

Question 22

Name a common alkali used in cleaning products.

Answer 22

Sodium hydroxide.

Question 23

Is baking soda an acid or alkali?

Answer 23

Alkali.

Question 24

What is the scientific name for baking soda?

Answer 24

Sodium bicarbonate.

Question 25

What alkali is used in drain cleaner?

Answer 25

Sodium hydroxide.

Question 26

What is ammonia used for?

Answer 26

As a cleaning product and in fertilisers.

Question 27

What happens when acids and alkalis react?

Answer 27

They neutralise each other.

Question 28

What is the name of the reaction between acids and alkalis?

Answer 28

Neutralisation.

Question 29

What is produced in a neutralisation reaction?

Answer 29

A salt and water.

Question 30

What is an indicator?

Answer 30

A substance that changes colour in acid or alkali.

Question 31

Name a natural indicator.

Answer 31

Red cabbage juice or litmus.

Question 32

What does litmus paper do?

Answer 32

Shows if a substance is acidic or alkaline.

Question 33

What colour is litmus paper in acid?

Answer 33

Red.

Question 34

What colour is litmus paper in alkali?

Answer 34

Blue.

Question 35

What colour is litmus paper in neutral solution?

Answer 35

Purple or no change.

Question 36

What is a universal indicator?

Answer 36

A mixture of dyes that show the full pH scale.

Question 37

What do strong acids have?

Answer 37

Very low pH (0–2).

Question 38

What do strong alkalis have?

Answer 38

Very high pH (12–14).

Question 39

What do weak acids have?

Answer 39

Higher pH than strong acids (3–6).

Question 40

What do weak alkalis have?

Answer 40

Lower pH than strong alkalis (8–11).

Question 41

What is the best way to measure pH accurately?

Answer 41

Using a pH probe or digital pH meter.

Question 42

What is a salt in chemistry?

Answer 42

A compound made from acid and alkali reaction.

Question 43

What acid and alkali make sodium chloride?

Answer 43

Hydrochloric acid and sodium hydroxide.

Question 44

What acid and alkali make potassium nitrate?

Answer 44

Nitric acid and potassium hydroxide.

Question 45

Why is neutralisation useful in farming?

Answer 45

To reduce soil acidity with lime.

Question 46

Why is toothpaste slightly alkaline?

Answer 46

To neutralise acids in the mouth.