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

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

Rewrite this equation to include state symbols.

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 number of moles of hydrochloric acid required to react exactly with $4.15 \mathrm{g}$ of sodium carbonate.

(${\mathrm{A}}_{\mathrm{r}}$ values: $\mathrm{C}=12.0, \mathrm{Na}=23.0, \mathrm{O}=16.0, \mathrm{H}=1.0, \mathrm{Cl}=35.5$).

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.