Unit 3b- Acids and Alkalis

Question 1

What type of salt does hydrochloric acid make?

Answer 1

Chlorides

Question 2

What type of salt does sulphuric acid make?

Answer 2

Sulphates

Question 3

What type of salt does nitric acid make?

Answer 3

Nitrates

Question 4

How do you make chloride salts?

Answer 4

React with hydrochloric acid

Question 5

How do you make sulphate salts?

Answer 5

React with sulphuric acid

Question 6

How do you make nitrate salts?

Answer 6

React with nitric acid

Question 7

Define acid in terms of pH

Answer 7

A substance with a pH of less than 7

Question 8

Define acids in terms of ions

Answer 8

A substance which releases H⁺ ions in solution

Question 9

What does (aq) stand for?

Answer 9

Aqueous: when something is dissolved in water. E.g. NaCl(aq) is salt water

Question 10

State the three common acids and give their formulae

Answer 10

Hydrochloric acid, HCl(aq), Sulphuric acid, H₂SO₄(aq), Nitric acid, HNO₃

Question 11

Name HCl(aq),

Answer 11

Hydrochloric acid

Question 12

Name H₂SO₄(aq)

Answer 12

Sulphuric acid,

Question 13

Name, HNO₃

Answer 13

Nitric acid,

Question 14

Which ions do the common acids form in solution?

Answer 14

HCl forms H⁺ and Cl⁻,

H₂SO₄ forms 2H⁺ and SO₄²⁻,

HNO₃ forms H⁺ and NO₃⁻

Question 15

What is a neutral solution?

Answer 15

A solution with a pH of 7. Water is an example.

Question 16

How do you measure pH?

Answer 16

With an indicator or pH probe.

Question 17

What is a base?

Answer 17

A metal oxide, hydroxide or carbonate that will react with an acid. E.g. copper oxide

Question 18

What is an alkali?

Answer 18

A soluble base. E.g. sodium hydroxide

Question 19

Which ions are always present in a solution of an alkali?

Answer 19

OH⁻

Question 20

Name OH⁻

Answer 20

Hydroxide ion

Question 21

What is a salt?

Answer 21

An ionic substance

Question 22

What type of salts are formed by the three main acids?

Answer 22

Hydrochloric acid produces chlorides,

sulphuric acid produces sulphates,

nitric acid produces nitrates

Question 23

What is a neutralisation reaction?

Answer 23

A reaction involving an acid that results in a neutral solution

Question 24

Which ions always react together in a neutralization reactions between acids and alkalis?

Answer 24

H⁺ and OH⁻

Question 25

Write the equation showing the reaction between H⁺ and OH⁻ ions

Answer 25

H⁺ + OH⁻ → H₂O

Question 26

metal + acid →

Answer 26

→ salt + hydrogen gas

Question 27

metal hydroxide + acid →

Answer 27

→ salt + water

Question 28

metal oxide + acid →

Answer 28

→ salt + water

Question 29

metal carbonate + acid →

Answer 29

→ salt + water + carbon dioxide

Question 30

How do you make a soluble salt from an acid?

Answer 30

React the acid with a base. E.g. to make copper sulphate react copper oxide with sulphuric acid

Question 31

If a salt is in solution, how do you extract it as a solid?

Answer 31

Allow the water to evaporate off and it will leave the salt behind as a solid.

Question 32

What is a strong acid?

Answer 32

An acid which completely splits up into its ions in water. E.g. when HCl is in water all the HCl molecules split up into H⁺ and Cl⁻

Question 33

What is a weak acid?

Answer 33

An acid which will have some molecules which do not split up into their ions. E.g. in ethanoic acid only some of the molecules will have split up into the ethanoate ion and H⁺ ions.

Question 34

What is the relationship between the strength of an acid and its pH?

Answer 34

As an acid increases in strength the pH decreases.

Question 35

What is a concentrated acid?

Answer 35

An acid where there are lots of acid particles in the water.

Question 36

What is a dilute acid?

Answer 36

An acid where there are fewer acid particles in the water.

Question 37

How is pH measured?

Answer 37

pH is related to the concentration of H⁺ in a solution.

Question 38

What is the test for hydrogen?

Answer 38

Give a squeaky pop with a lit splint

Question 39

What is the test for carbon dioxide?

Answer 39

Limewater turns from clear to cloudy