Formulae & Equations (Edexcel International A Level Chemistry)

Exam Questions

31 mins11 questions
1a
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5 marks

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.

q19a-paper-1-jan-2022-edexcel-ial-chemistry

Step 3 After heating for two minutes, the crucible containing the magnesium sulfate was allowed to cool and was reweighed.


i)
Complete the table of results.

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)

ii)

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)

1b2 marks

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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1a
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1 mark

This question is about iron and some of its compounds.

Complete the table to show the numbers of subatomic particles in 56Fe2+.

Number of protons Number of neutrons Number of electrons
     
1b
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2 marks

A sample of iron contains the following isotopes.

Isotope Percentage abundance
54Fe 5.84
56Fe 91.68
57Fe 2.17
58Fe 0.31


Calculate the relative atomic mass of this sample of iron.
Give your answer to three significant figures.

1c2 marks

Magnesium reacts with aqueous iron(II) sulfate in a displacement reaction.

Write the ionic equation for this reaction.
Include state symbols.

1d
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3 marks

25.00 g of a compound contains 6.98 g of iron and 6.03 g of sulfur.

The remaining mass is oxygen.

Calculate the empirical formula of this compound.

[Ar values: O = 16.0 S = 32.1 Fe = 55.8]

1e
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5 marks

When 6.95 g of FeSO4xH2O is heated, 2.00 g of iron(III) oxide, 0.80 g of sulfur dioxide and 1.00 g of sulfur trioxide are produced.
The only other product is water.

Deduce the overall equation for the reaction using these data.
State symbols are not required.

You must show your working.

[Ar values: H = 1.0   O = 16.0    S = 32.1    Fe = 55.8]

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