VCE Chemistry Unit 1
Empirical Formulae of a Hydrated Salt
Aim:
To identify the ratio of water present in a hydrated salt.
Equipment:
 Balance
 Crucible & lid
 Bunsen burner
 Hydrated barium chloride (2 g)
 Pipe clay triangle
 Tripod
 Crucible tongs
Pre-Lab Questions
1. Create a results table for this experiment.
2. List 3 safety concerns that are part of this method and how you will address them in the
lab.
3. Explain why Step 1 is performed prior to the rest of the experiment.
Method
1. Obtain a clean and dry crucible and lid, and heat them strongly for 5 minutes over a
Bunsen flame.
2. Weigh the crucible and lid on an accurate balance.
3. Add approximately 2 g of barium chloride to the crucible and immediately re-weigh.
4. Place the lid on the crucible, leaving a small gap, and heat for 5 minutes with a low flame.
5. Heat the crucible strongly for a further 20 minutes and re-weigh.
6. Repeat strong heating for a further 5 minutes, and then.
7. Repeat Step 6 until a consistent mass is obtained.
Post-Lab Questions
1. Determine the mass of anhydrous barium chloride remaining at the end of the
experiment.
2. Determine the mass of water driven off in the experiment.
3. Using your answers to Q1&2, calculate the ratio of barium chloride to water.
4. Therefore, write the formula of hydrated barium chloride.