Identify laboratory apparatus and define solubility, explaining factors affecting it and how to determine it.

1. (a)

• C: Funnel
• E: Measuring cylinder

1. (b)
One use of apparatus D (beaker) is to hold liquids or mix substances.

1. (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 A (conical flask) or D (beaker).

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

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

• Temperature
• Nature of the solute and solvent

2. (c)
To find the mass of salt that dissolves in $100 \text{ cm}^3$ of water at the given temperature:

1. Measure $100 \text{ cm}^3$ of water into a beaker.
2. Add the salt gradually to the water while stirring continuously at the specified temperature.
3. Continue adding salt until no more dissolves and a small amount of undissolved salt remains at the bottom of the beaker.
4. Carefully decant or filter the saturated solution into a pre-weighed evaporating dish.
5. Gently heat the evaporating dish to evaporate all the water, leaving the dry salt behind.
6. Allow the dish and dry salt to cool, then weigh them.
7. Subtract the mass of the empty evaporating dish from the mass of the dish with dry salt to find the mass of the dissolved salt.

2. (d)
You would know that the solution is saturated when no more salt dissolves, and any additional salt added remains as undissolved solid at the bottom of the container.

2. (e)
One use of the information obtained from this experiment is in the purification of substances by crystallization.