2(g) Acids, bases and salt preparations

Question 1

Nitrates

Answer 1

All nitrates are soluble

Question 2

Chlorides

Answer 2

Common chlorides are soluble, except those of silver and lead(II)

Question 3

Sulfates

Answer 3

Common sulfates are soluble, except for those of barium, calcium and lead(II)

Question 4

Carbonates

Answer 4

Common carbonates are insoluble, except for those of sodium, potassium and ammonium

Question 5

Hydroxides

Answer 5

common hydroxides are insoluble except for those of sodium, potassium and calcium (calcium hydroxide is slightly soluble).

Question 6

Common sodium, potassium and ammonium compounds

Answer 6

Soluble

Question 7

Acids (in terms of proton transfer)

Answer 7

Proton Donor

Question 8

Alkalis (in terms of proton transfer)

Answer 8

Proton Acceptor

Question 9

Salt equations: MASH

Answer 9

Metal + Acid -> Salt + Hydrogen

Question 10

Salt equations: BAWS

Answer 10

Base + Acid -> Water + Salt

Question 11

Salt equations: AAWS

Answer 11

Acid + Alkali -> Water + Salt

Question 12

Salt equations: CAWCS

Answer 12

Metal carbonate + Acid -> Water + Carbon Dioxide + Salt

Question 13

2.39 describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an insoluble reactant

Answer 13

1. Add metal/metal oxide/metal carbonate in excess to the acid (to react all the acid)
2. Remove excess through filtration
3. Heat filtrate (in evaporating basin + bunsen burner) to reduce by half/until saturated
4. Remove heat
5. Leave in a warm place to dry

Question 14

2.40C describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an acid and alkali

Answer 14

1. Add reactants to beaker and mix
2. Filter
3. Heat filtrate (in evaporating basin + bunsen burner) to reduce by half/until saturated
4. Remove heat
5. Leave in a warm place to dry

Question 15

2.41C describe an experiment to prepare a pure, dry sample of an insoluble salt, starting from two soluble reactants

Answer 15

1. Add reactants to beaker and mix
2. Filter
3. Rinse with distilled water (to remove impurities)
4. Leave in a warm place to dry

Question 16

2.42 practical: prepare a sample of pure, dry hydrated copper(II) sulfate crystals starting from copper(II) oxide

Answer 16

1. Add copper oxide in excess to sulfuric acid and stir with glass rod
2. Warm with bunsen burner
3. Solution turns blue as reaction occurs
4. To remove excess copper oxide, filter
5. Heat filtrate and reduce by half
6. Leave in a warm place to dry

Question 17

2.43C practical: prepare a sample of pure, dry lead(II) sulfate

Answer 17

1. Add lead nitrate to sodium sulfate solution
2. White precipitate of lead sulfate is formed
3. Filter
4. Rinse with distilled water.
5. Leave in a warm place to dry

Question 18

Alkalis

Answer 18

Bases that are soluble in water

Question 19

What substances can act as bases?

Answer 19

metal oxides, metal hydroxides, ammonia, metal carbonates