Magnesium and its compounds have many important industrial uses.
Magnesium is an abundant metal found in minerals such as magnesite, rather than as a pure native element in the Earth's crust.
Suggest why magnesium is never found as a pure element in the Earth's crust.
Magnesium can be processed and extracted using a multi-stage process:
Which stage involves a neutralisation reaction?
Suggest the name of the other product formed in Stage 1.
What happens to the ions in magnesium chloride during melting?
The ionic half-equation for the reaction at the negative electrode in Stage 4 is:
Mg2++2e−→Mg \text{Mg}^{2+} + 2\text{e}^- \rightarrow \text{Mg} Mg2++2e−→MgWrite the ionic half-equation for the reaction at the positive electrode.
A manufacturer makes a batch of magnesium by electrolysing molten magnesium chloride. Use Ar(Mg)=24A_r(\text{Mg}) = 24Ar(Mg)=24 and Ar(Cl)=35.5A_r(\text{Cl}) = 35.5Ar(Cl)=35.5.
Calculate the mass of magnesium chloride (MgCl2\text{MgCl}_2MgCl2) needed to make 120 kg120\text{ kg}120 kg of magnesium.
Calculate the amount, in moles, of electrons needed to make 120 kg120\text{ kg}120 kg of magnesium.
Magnesium oxide can be used to make magnesium sulfate by this reaction:
MgO(s)+H2SO4(aq)→MgSO4(aq)+H2O(l) \text{MgO(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{MgSO}_4\text{(aq)} + \text{H}_2\text{O(l)} MgO(s)+H2SO4(aq)→MgSO4(aq)+H2O(l)A student is provided with a beaker of dilute sulfuric acid. Outline the steps she should use to obtain a pure sample of hydrated magnesium sulfate crystals using this reaction.
