Heating in a crucible

Question 1

crucible method

Answer 1

1) Weigh an empty clean dry crucible and lid
2) Add 2g of hydrated calcium sulfate to the crucible and weigh
again
3) Heat strongly with a Bunsen for a couple of minutes
4) Allow to cool
5) Weigh the crucible and contents again
6) Heat crucible again and reweigh until you reach a constant mass

Question 2

why should large amounts of hydrated calcium sulfate not be used

Answer 2

because the decomposition is
likely to be incomplete

Question 3

why should a lid be used

Answer 3

because it improves the accuracy of the
experiment by preventing loss of solid
from the crucible

Question 4

why should small conc of the solid not be used

Answer 4

the percentage
uncertainties in weighing will be too
high

Question 5

why does the crudible need to be dry

Answer 5

because a wet crucible would give an inaccurate result

it would cause mass loss to be too large as the water would be lost when heating