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3.1 Introducing chemical reactions

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Question 6

A pilot process produces hydrogen by reacting magnesium with hydrochloric acid. Magnesium is added in excess. One batch of the acid contains 5.25 kg of hydrogen chloride.

Mg+2HCl→MgCl2+H2\text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2Mg+2HCl→MgCl2​+H2​

Relative atomic mass (ArA_rAr​): H = 1.0, Cl = 35.5

Calculate, to 3 significant figures, the mass of hydrogen produced when all the hydrogen chloride in this batch has reacted.

Give the mass in kg.

Mass of hydrogen produced = ............... kg

[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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