AS Required Practicals

Question 1

Safety & Hazards

Answer 1

Irritant - dilute acid and alkalis- wear goggles
Corrosive- stronger acids and alkalis wear goggles
Flammable – keep away from naked flames
Toxic – wear gloves- avoid skin contact- wash hands after use
Oxidising- Keep away from flammable / easily oxidized materials

Question 2

Use of heating in a crucible Practical

Answer 2

• method could be used for measuring mass loss in various thermal decomposition reactions & also mass gain when reacting magnesium in oxygen

Question 3

What happens in crystallization practical?

Answer 3

The water of crystallisation in calcium sulphate crystals removed as water vapour by heating

Question 4

Method of Crystallisation Practical?

Answer 4

Weigh an empty clean dry crucible and lid
•Add 2g of hydrated calcium sulphate to the crucible and weigh again
•Heat strongly with a Bunsen for a couple of minutes •Allow to cool
•Weigh the crucible and contents again
•Heat crucible again and reweigh until you reach a constant mass (do this to ensure reaction is complete).

Question 5

State one way to improve crystallisation practical?

Answer 5

• Lid improves accuracy of experiment - it prevents loss of solid from the crucible but should be loose
  fitting to allow gas to escape