Magnesium reacts with hydrochloric acid as shown in the equation.
Mg+2HCl→MgCl2+H2 \text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2 Mg+2HCl→MgCl2+H21.2 g of magnesium reacts completely with hydrochloric acid to form 4.75 g of magnesium chloride and 0.10 g of hydrogen.
Show, by calculation, that the law of conservation of mass applies to this reaction.
(Relative atomic masses, ArA_rAr: H=1\text{H} = 1H=1; Mg=24\text{Mg} = 24Mg=24; Cl=35.5\text{Cl} = 35.5Cl=35.5)
258 exam-style questions on Edexcel GCSE Chemistry Calculations involving masses. Each one has a worked solution and a mark scheme showing where the marks go.