Chemistry – PLC Task
PLC 49- Assessed Task
Unit No.
Topic Area
Key Concept
Chemistry
Calculations
Calculate percentage yield (H Tier)
2
Difficulty
Name:

Class:
1. (a) The formula for the chemical compound magnesium sulphate is MgSO4.
Calculate the relative formula mass (Mr)of this compound. (Show your working.)
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[2 marks]
(b) Magnesium sulphate can be made from magnesium and dilute sulphuric acid.
This is the equation for the reaction.
Mg + H2SO4 → MgSO4 + H2
Calculate the mass of magnesium sulphate that would be obtained from 4g of magnesium.
(Show your working.)
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Answer..................................... g
[2 marks]
(c) Only 2g of magnesium sulphate is actually created by a student. Calculate the percentage
yield.
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St Peter’s Catholic Comprehensive School – Science Department 2013
Chemistry – PLC Task
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Answer..................................... %
[3 marks]
2. The balanced symbol equation for the reaction is
H2 (g) + Cl2 (g) → 2HCl (g)
Starting with 2 g of hydrogen, what mass of hydrogen chloride would be produced?
(Relative atomic masses: H = 1; Cl = 35.5)
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Mass of hydrogen chloride = ...................................... g
[3 marks]
Total Score
Out of:
Percentage Score
10
TIP – To Improve Progress
How you can make further progress
0-39% = Practice Task 1
40-79% = Improvement Task 1
80%+ = Extension Task 1
St Peter’s Catholic Comprehensive School – Science Department 2013