Alternative To Practical

Question 0

Name 2 WEAK acids.

Answer 0

Ethanoic acid (4), Carbon dioxide (aq) (6)

Question 1

Name 3 STRONG acids.

Answer 1

Nitric acid (1), Hydrochloric acid (1), Sulphuric acid (1).

Question 2

Name 2 WEAK alkalis.

Answer 2

Ammonia (aq) (11), Sodium hydrogen carbonate (aq) (8).

Question 3

Name 2 STRONG alkalis.

Answer 3

Lithium hydroxide (13), Sodium hydroxide (13).

Question 4

Explain the 7 steps to thermometric titrations (Usually used to work out an unknown concentration)

Answer 4

1. Allow reacting solutions to stand for a while, so both are at the same (room) temperature before reaction.
2. Use a pipette to measure out an accurate amount of alkali at a known concentration into a polystyrene cup.
3. Measure the temperature of the alkali.
4. Add small, known, volumes of acid from a burette (e.g. 2.00cm3).
5. Mix and measure the maximum temperature reached.
6. Keep on taking temperature measurements while the temperature declines.
7. Plot a graph of the results and use extrapolation of two straight lines. The point where the lines cross is the neutralisation point.