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3.1 Introducing chemical reactions

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Question 13
F

When 3.0 g of magnesium burns completely in air, 5.0 g of magnesium oxide is made.

A student heats 7.2 g of magnesium in an open crucible. The student stops heating before all the magnesium has reacted. The mass of solid in the crucible is now 10.4 g.

What mass of magnesium has not reacted?

[1]
A

2.4 g

B

3.2 g

C

4.8 g

D

5.3 g

Markscheme

3.1 Introducing chemical reactions Questions

  1. GCSE
  2. /Chemistry
  3. /3.1 Introducing chemical reactions

55 exam-style questions on OCR GCSE Chemistry 3.1 Introducing chemical reactions, covering 3.1.1 Writing formulae and balanced chemical equations, 3.1.2 Formulae of compounds from ions, and state symbols, 3.1.3 Conservation of mass and observed changes in mass, 3.1.4 Half equations and balanced ionic equations, 3.1.5 The mole and the Avogadro constant, and 3.1.6 Stoichiometry, limiting reactants and reacting masses. Each one has a worked solution and a mark scheme showing where the marks go.

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