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2.6 Calculations involving masses

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Question 17
F

Epsom salts are hydrated magnesium sulfate, MgSO4⋅7H2O\mathrm{MgSO_{4}\cdot 7H_{2}O}MgSO4​⋅7H2​O. Relative atomic masses: H=1\mathrm{H} = 1H=1, O=16\mathrm{O} = 16O=16, Mg=24\mathrm{Mg} = 24Mg=24, S=32\mathrm{S} = 32S=32.

What is the percentage by mass of oxygen in Epsom salts?

[1]
A

26.0%26.0\%26.0%

B

45.5%45.5\%45.5%

C

53.3%53.3\%53.3%

D

71.5%71.5\%71.5%

Markscheme

2.6 Calculations involving masses Questions

  1. GCSE
  2. /Chemistry
  3. /2.6 Calculations involving masses

55 exam-style questions on Edexcel GCSE Chemistry 2.6 Calculations involving masses, covering 2.6.1 Relative formula mass and percentage composition, 2.6.2 Empirical and molecular formulae, 2.6.3 Conservation of mass, 2.6.4 Reacting masses and concentration in g dm⁻³, 2.6.5 The mole and the Avogadro constant, and 2.6.6 Limiting reactants and stoichiometry. Each one has a worked solution and a mark scheme showing where the marks go.

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