Practicals

Question 1

What is the practical that can be carried out to test how temperature affects solubility?

Answer 1

1. Make a saturated solution of ammonium chloride
2. Stir the solution and place it in a water bath at 25 degrees Celsius.
3. After 5 minutes, check that all of the excess solid has sunk to the bottom of the tube and use a thermometer to check that the solution has reached 25 degrees
4. Weigh an empty evaporating basin and then pour some of the solution into the basin without pouring in the excess solid.
5. Re-weigh the basin and then gently heat it to remove all the water.
6. Once all the water has evaporated, you will be left with pure ammonium chloride. Re-weigh the basin
7. Repeat this twice more but with different temperatures and use the different masses to work out the solubility at each temperature

Question 2

How can you use filtration and crystallization to separate rock salt?

Answer 2

Rock salt is a mixture of sand and salt. They are both compounds but salt dissolves in water whereas sand doesn’t.

1. Grind up the rock salt
2. Dissolve it in a beaker
3. Filter the liquid through a filter paper
4. Crystallize the liquid and you will be left with pure salt