ST.8 Acids and Bases N5 (CCS)

Question 1

What are alkalis?

Answer 1

Soluble bases

Question 2

When are alkaline solutions formed?

Answer 2

When metal oxides are dissolved in water

Question 3

When are acidic solutions formed?

Answer 3

When non-metal oxides are dissolved in water

Question 4

Are bases soluble in water?

Answer 4

No

Question 5

Why are acid and alkaline solutions able to conduct electricity?

Answer 5

They have free ions ables to carry the charge

Question 6

Name 2 strong acids

Answer 6

Hydrochloric acid and sulfuric acid

Question 7

What is meant by a “strong acid”?

Answer 7

They can fully dissociate into their component ions

Question 8

What is meant by a “weak acid”?

Answer 8

Weak acids can only partially dissociate into their component ions

Question 9

What happens when an acid is diluted?

Answer 9

The concentration of H+ ions decreases and the pH moves towards 7

Question 10

Give 3 examples of weak acids

Answer 10

Ethanoic acid, citric acid and carbonic acid

Question 11

What happens when an alkali is diluted?

Answer 11

The concentration of OH- decreases and the pH moves towards 7

Question 12

What determines how well an acid or alkali conducts?

Answer 12

How concentrated the acid or alkali is

Question 13

What does water break down into?

Answer 13

H+ and OH- ions

Question 14

What does ⇌ mean?

Answer 14

That a dissociation is reversible

Question 15

What does dissociation mean?

Answer 15

The process in which molecules separate or split into other things such as atoms, ions, or radicals

Question 16

What is equilibrium?

Answer 16

A small proportion of water breaking down into H+ and OH- ions and then reacting again to produce water. It is present in water and all aqueous solutions

Question 17

What ratio of ions are in acids, alkalis and neutral solutions?

Answer 17

Acid - H+ > OH-
Alkali - H+ < OH-
Neutral H+ = OH-

Question 18

What experiment changed a pH by 1?

Answer 18

1 in 10 dilution

Question 19

Give examples of some bases

Answer 19

Metal oxides, metal hydroxides, metal carbonates and ammonia

Question 20

What is a neutralisation reaction?

Answer 20

When a base reacts with an acid to form a salt and water

Question 21

List 3 neutralisation equations

Answer 21

Metal oxide + acid —-> salt + water
Metal hydroxide + acid —-> salt + water
Metal carbonate + acid —-> salt + water + carbon dioxide

Question 22

Give acid names with salt endings

Answer 22

Hydrochloric - chloride
Sulfuric - sulfide
Nitric - nitride

Question 23

Explain why water is always formed in neutralisation reactions

Answer 23

The H+ ion from the acid joins the OH- ion from the alkali
(H+ + OH- —-> H2O)

Question 24

What is a spectator ion?

Answer 24

Ions that are present in the reaction but are unchanged by the reaction so must be the same state from start to end
i.e H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) —> Na+(aq) + Cl-(aq) + H2O (l)
becomes…
H+(aq) + OH-(aq) —-> H2O (l)

Question 25

What can neutralisation reactions be used for?

Answer 25

To prepare soluble salts

Question 26

What can also be used to prepare soluble salts?

Answer 26

Titrations

Question 27

How can a titration prepare a soluble salt?

Answer 27

Once the volumes of acid and alkali have been recorded, the reaction can be repeated without the indicator to produce an uncontaminated salt solution. The solution can then be evaporated to dryness

Question 28

How can insoluble metal carbonates and insoluble metal oxides be used to produce soluble salts?

Answer 28

Excess base is added to the appropriate acid, the mixture is filtered and the filtrate is evaporated to dryness