An aqueous solution of $25.0 {\mathrm{cm}}^3$ sodium carbonate of concentration $0.0200 \mathrm{mol} {\mathrm{dm}}^{-3}$ is titrated with hydrochloric acid. The volume of hydrochloric acid required to exactly react with the sodium carbonate is $12.50 {\mathrm{cm}}^3$. Calculate the number of moles of sodium carbonate present in the solution of sodium carbonate.

Solid sodium carbonate reacts with aqueous hydrochloric acid to form aqueous sodium chloride, carbon dioxide and water.

${\mathrm{Na}}_2{\mathrm{CO}}_3+2\mathrm{HCl}\to 2\mathrm{NaCl}+{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}$

Calculate the volume of this number of moles of carbon dioxide at r.t.p. ($1 \mathrm{mol}$ of gas occupies $24 {\mathrm{dm}}^3$ at r.t.p.).

Hydrocarbons are compounds of carbon and hydrogen only. Hydrocarbon $\mathrm{Z}$ is composed of $80\%$ carbon and $20\%$ hydrogen.

a. Calculate the empirical formula of hydrocarbon $\mathrm{Z}$. (${\mathrm{A}}_{\mathrm{r}}$ values: $\mathrm{C}=12.0, \mathrm{H}=1.0$).

b. The molar mass of hydrocarbon $\mathrm{Z}$ is $30.0 \mathrm{g} {\mathrm{mol}}^{-1}$. Deduce the molecular formula of this hydrocarbon.

When $50 {\mathrm{cm}}^3$ of hydrocarbon $\mathrm{Y}$ is burnt, it reacts with exactly $300 {\mathrm{cm}}^3$ of oxygen to form $200 {\mathrm{cm}}^3$ of carbon dioxide. Water is also formed in the reaction. Construct the equation for this reaction. Explain your reasoning.

Propane has the molecular formula ${\mathrm{C}}_3{\mathrm{H}}_8$. Calculate the mass of $600 {\mathrm{cm}}^3$ of propane at r.t.p. ($1 \mathrm{mol}$ of gas occupies $24 {\mathrm{dm}}^3$ at r.t.p.).

(${\mathrm{A}}_{\mathrm{r}}$ values: $\mathrm{C}=12.0, \mathrm{H}=1.0$).

When sodium reacts with titanium chloride $\left({\mathrm{TiCl}}_4\right)$, sodium chloride $\left(\mathrm{NaCl}\right)$ and titanium $\left(\mathrm{Ti}\right)$ are produced. Construct the balanced symbol equation for the reaction.

When sodium reacts with titanium chloride $\left({\mathrm{TiCl}}_4\right)$, sodium chloride $\left(\mathrm{NaCl}\right)$ and titanium $\left(\mathrm{Ti}\right)$ are produced. Calculate the mass of titanium produced from $380 \mathrm{g}$ of titanium chloride. Give your answer to $3$ significant figures. (${\mathrm{A}}_{\mathrm{r}}$ values: $\mathrm{Ti}=47.9, \mathrm{Cl}=35.5$).