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3.2 Use of amount of substance in relation to masses of pure substances

3.2 Use of amount of substance in relation to masses of pure substances

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Question 14

This question is about extraction and displacement reactions.

a.

The reduction of titanium(IV) chloride with magnesium has a high activation energy.

What is meant by 'activation energy'?

[1]
b.

A reaction mixture contains 0.36 kg0.36\text{ kg}0.36 kg of magnesium and 1.52 kg1.52\text{ kg}1.52 kg of titanium(IV) chloride.

The equation for the reaction is:

TiCl4+2Mg→Ti+2MgCl2 \text{TiCl}_4 + 2\text{Mg} \rightarrow \text{Ti} + 2\text{MgCl}_2 TiCl4​+2Mg→Ti+2MgCl2​

Show that magnesium is the limiting reactant.

Relative atomic masses (ArA_rAr​): Mg=24\text{Mg} = 24Mg=24, Cl=35.5\text{Cl} = 35.5Cl=35.5, Ti=48\text{Ti} = 48Ti=48

[5]
c.

Magnesium displaces copper from copper(II) sulfate solution.

Complete the ionic equation for the reaction. You should include state symbols.

Mg(s)+Cu2+(aq)→________+________ \text{Mg(s)} + \text{Cu}^{2+}\text{(aq)} \rightarrow \text{\_\_\_\_\_\_\_\_} + \text{\_\_\_\_\_\_\_\_} Mg(s)+Cu2+(aq)→________+________
[2]
d.

Explain why the reaction between magnesium atoms and copper(II) ions is both oxidation and reduction.

[2]
Markscheme

3.2 Use of amount of substance in relation to masses of pure substances Questions

  1. GCSE
  2. /Chemistry
  3. /3.2 Use of amount of substance in relation to masses of pure substances

38 exam-style questions on AQA GCSE Chemistry 3.2 Use of amount of substance in relation to masses of pure substances, covering 3.2.1 Moles (HT only), 3.2.2 Amounts of substances in equations (HT only), 3.2.3 Using moles to balance equations (HT only), 3.2.4 Limiting reactants (HT only), and 3.2.5 Concentration of solutions. Each one has a worked solution and a mark scheme showing where the marks go.

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