Salt Preparations (mocks)

Question 1

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

Answer 1

1. Measure acid into beaker
2. Warm up acid to speed up reaction
3. Add solid until no more will dissolve
4. Filter to remove excess solid
5. Filtrate contains solution of soluble salt
6. Heat filtrate until saturation point
7. Leave overnight to form crystals
8. Dry in a warm oven.

Question 2

How would you prepare an insoluble salt from two soluble reactants?

Answer 2

By precipitation

Question 3

How would you prepare a soluble salt containing sodium, potassium and ammonium?

Answer 3

Titration

Question 4

Give the formula for a titration

Answer 4

Soluble base + acid —> salt + water

Question 5

Give the 3 possible formulas for an insoluble base + acid

Answer 5

Metal oxide + acid -> salt + water
Metal carbonate + acid -> salt + water + CO2
Metal hydroxide + acid -> salt + water

Question 6

Describe a titration

Answer 6

1. Fill burette with acid
2. Pipette base into conical flask
3. Add indicator
4. Add acid gradually until colour change
5. Record volume added
6. Repeat until 3+ concordant results
7. Make an average