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3.1 Introducing chemical reactions

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Question 31

A gas sample contains the substances shown in the table.

SubstanceMass
Nitrogen dioxide, NO2\mathrm{NO_{2}}NO2​3.45 g
Oxygen, O2\mathrm{O_{2}}O2​1.60 g

Relative atomic masses (ArA_rAr​): N = 14.0, O = 16.0

The Avogadro constant is 6.02 × 1023.

Calculate the total number of atoms in the sample.

[4]
Markscheme

3.1 Introducing chemical reactions Questions

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

134 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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