Limewater is a solution of calcium hydroxide. Give the formula of calcium hydroxide.

Limewater is a solution of calcium hydroxide. Explain why calcium hydroxide is used in agriculture.

Exactly $0.1 \mathrm{moles}$ each of calcium hydroxide and barium hydroxide are added to separate beakers containing $100 {\mathrm{cm}}^3$ of water and stirred to form saturated solutions. Explain which solution has the higher pH value.

For the following reaction, state which element is oxidised and which is reduced, and give the changes in oxidation number.

$\mathrm{Sr} + {\mathrm{Cl}}_2 \to {\mathrm{SrCl}}_2$

For the following reaction, state which element is oxidised and which is reduced, and give the changes in oxidation number.

$\mathrm{Sr}+ 2{\mathrm{H}}_2\mathrm{O} \to \mathrm{Sr}{\left(\mathrm{OH}\right)}_2 + {\mathrm{H}}_2$

For the following reaction, state which element is oxidised and which is reduced, and give the changes in oxidation number.

$2\mathrm{Mg} + {\mathrm{CO}}_2 \to 2\mathrm{MgO} + \mathrm{C}$