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

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Question 10
Medium

This question is about displacement and redox reactions.

a.

The displacement reaction between magnesium and iron(III) oxide has a high activation energy.

What is meant by 'activation energy'?

[1]
b.

A mixture contains 1.20 kg1.20\text{ kg}1.20 kg of magnesium and 4.50 kg4.50\text{ kg}4.50 kg of iron(III) oxide.

The equation for the reaction is:

3Mg+Fe2O3→3MgO+2Fe3\text{Mg} + \text{Fe}_2\text{O}_3 \rightarrow 3\text{MgO} + 2\text{Fe}3Mg+Fe2​O3​→3MgO+2Fe

Show that magnesium is the limiting reactant.

Relative atomic masses (ArA_rAr​): O=16\text{O} = 16O=16, Mg=24\text{Mg} = 24Mg=24, Fe=56\text{Fe} = 56Fe=56

[4]
c.

Magnesium displaces zinc from zinc sulfate solution.

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

Mg(s)+Zn2+(aq)→________+________\text{Mg(s)} + \text{Zn}^{2+}\text{(aq)} \rightarrow \text{\_\_\_\_\_\_\_\_} + \text{\_\_\_\_\_\_\_\_}Mg(s)+Zn2+(aq)→________+________

[2]
d.

Explain why the reaction between magnesium atoms and zinc ions is both oxidation and reduction.

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

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