This question is about the amount of water of crystallisation in hydrated magnesium sulfate, MgSO4 ·xH2O.
The value of x in the formula was determined in an experiment.
Procedure
Step 1 | A crucible was weighed, a spatula measure of hydrated magnesium sulfate was added and the crucible was reweighed. |
Step 2 |
The crucible containing the hydrated magnesium sulfate was heated using the apparatus shown. |
Step 3 | After heating for two minutes, the crucible containing the magnesium sulfate was allowed to cool and was reweighed. |
Measurement | Mass / g |
Mass of empty crucible | 21.21 |
Mass of crucible and hydrated magnesium sulfate before heating | 26.71 |
Mass of crucible and magnesium sulfate after heating for two minutes | 24.12 |
Mass of magnesium sulfate after heating for two minutes | |
Mass of water lost |
(1)
Use these results to calculate the value of x in MgSO4 ·xH2O.
Give your answer to the nearest whole number.
[Ar values: H = 1.0 O = 16.0 Mg = 24.3 S = 32.1]
(4)
The correct value of x is greater than the value calculated in (a)(ii).
Suggest a way of improving the method to obtain a more accurate result, using the same apparatus.
Justify your answer.
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