Magnesium carbonate decomposes when heated. The equation for the reaction is
MgCO3→MgO+CO2 \text{MgCO}_3 \rightarrow \text{MgO} + \text{CO}_2 MgCO3→MgO+CO2Calculate the maximum mass of MgO\text{MgO}MgO that could be obtained when 42 tonnes of MgCO3\text{MgCO}_3MgCO3 is decomposed.
Give the unit.
[Mr of MgO=40;Mr of MgCO3=84;1 tonne=106 g][M_r \text{ of MgO} = 40; \quad M_r \text{ of MgCO}_3 = 84; \quad 1 \text{ tonne} = 10^6 \text{ g}][Mr of MgO=40;Mr of MgCO3=84;1 tonne=106 g]
mass of MgO = ______ unit ______
Magnesium hydroxide, Mg(OH)2\text{Mg(OH)}_2Mg(OH)2, forms when water is added to magnesium oxide. Give the chemical name of magnesium hydroxide.
Magnesium hydroxide is often used as an antacid to neutralise stomach acid.
A chemist neutralises 50.0 cm3 of 0.400 mol/dm3 hydrochloric acid with magnesium hydroxide.
Mg(OH)2+2HCl→MgCl2+2H2O \text{Mg(OH)}_2 + 2\text{HCl} \rightarrow \text{MgCl}_2 + 2\text{H}_2\text{O} Mg(OH)2+2HCl→MgCl2+2H2OCalculate the amount, in moles, of HCl\text{HCl}HCl that is neutralised.
amount of HCl = ______ mol\text{mol}mol
Calculate the minimum mass, in grams, of Mg(OH)2\text{Mg(OH)}_2Mg(OH)2 required to neutralise the HCl\text{HCl}HCl.
[Mr of Mg(OH)2=58][M_r \text{ of Mg(OH)}_2 = 58][Mr of Mg(OH)2=58]
minimum mass of Mg(OH)2_22 = ______ g\text{g}g
A clear solution of barium hydroxide, Ba(OH)2\text{Ba(OH)}_2Ba(OH)2, is made by dissolving barium hydroxide in excess water. This solution is left exposed to air. The solution slowly goes milky as a faint white precipitate forms. Explain why a faint white precipitate forms.
80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.