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5.1 Monitoring chemical reactions

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Question 9
F

A student wants to make 6.45 g of magnesium oxide by burning magnesium in air.

2Mg+O2→2MgO \mathrm{2Mg + O_{2} \rightarrow 2MgO} 2Mg+O2​→2MgO

The percentage yield of the student's method is 80.0%.

Relative atomic mass (ArA_rAr​): O = 16.0 Mg = 24.3

What mass of magnesium should the student start with?

[1]
A

3.11 g

B

3.89 g

C

4.86 g

D

9.72 g

Markscheme

5.1 Monitoring chemical reactions Questions

  1. GCSE
  2. /Chemistry
  3. /5.1 Monitoring chemical reactions

57 exam-style questions on OCR GCSE Chemistry 5.1 Monitoring chemical reactions, covering 5.1.1 The technique of titration, 5.1.2 Theoretical mass, percentage yield and atom economy, 5.1.3 Concentration of a solution in mol/dm3, 5.1.4 Concentration calculations and titration results, 5.1.5 Molar gas volume and volumes of gases in reactions, and 5.1.6 Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.

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