Identify laboratory apparatus and explain the concept of solubility with an experiment procedure.

1. Laboratory Apparatus

a) The names of the apparatus are:

• C: Funnel
• E: Measuring cylinder

b) One use of apparatus D (beaker) in the laboratory is to hold and mix liquids.

c)

• (i) To measure a fixed volume of liquid, you would use apparatus E (measuring cylinder).
• (ii) To hold a liquid while mixing, you would use apparatus D (beaker) or A (conical flask).

2. Solubility Experiment

a) Solubility is the maximum mass of a solute that can dissolve in a given mass (or volume) of a solvent at a specific temperature to form a saturated solution.

b) Two factors that affect the solubility of a solid in a liquid are:

• Temperature: Generally, solubility of solids increases with increasing temperature.
• Nature of the solute and solvent: "Like dissolves like" – polar solutes dissolve in polar solvents, and non-polar solutes dissolve in non-polar solvents.

c) Procedure to find the mass of salt that dissolves in $100 \text{ cm}^3$ of water at a given temperature:

1. Measure $100 \text{ cm}^3$ of water using a measuring cylinder and pour it into a beaker.
2. Heat the water to the specified temperature and maintain it using a water bath or hot plate.
3. Add the salt gradually to the water while stirring continuously until no more salt dissolves and a small amount of undissolved salt remains at the bottom of the beaker. This indicates a saturated solution has formed.
4. Carefully decant the saturated solution or filter it to separate the undissolved salt.
5. Transfer the clear saturated solution to a pre-weighed evaporating dish.
6. Gently heat the evaporating dish to evaporate all the water, leaving the dissolved salt behind.
7. Allow the evaporating dish and dry salt to cool, then weigh it.
8. Subtract the mass of the empty evaporating dish from the mass of the dish with the dry salt to find the mass of the dissolved salt.

d) You would know that the solution is saturated when no more salt dissolves, and excess solid salt remains undissolved at the bottom of the container, even after thorough stirring.

e) One use of the information obtained from this experiment (solubility data) is to prepare solutions of specific concentrations for various chemical reactions or experiments.