Calculate the molecular masses of $C_2H_4$,$NH_3$ and $CH_3OH$.

Calculate the molecular masses of $H_2$,$O_2$ and $Cl_2$.

Calcium chloride when dissolved in water dissociates into its ions according to the following equation:
$CaCl_{2}(aq) \rightarrow Ca^{2+}(aq) + 2Cl^{-}(aq)$
Calculate the number of ions obtained from $CaCl_{2}$ when $222 \, g$ of it is dissolved in water.

Verify by calculating that:
$(a)$ $5 \, mol$ of $CO_2$ and $5 \, mol$ of $H_2O$ do not have the same mass.
$(b)$ $240 \, g$ of calcium and $240 \, g$ of magnesium elements have a mole ratio of $3:5$.

$A$ silver ornament of mass $m \, g$ is polished with gold equivalent to $1\%$ of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.

$A$ gas jar contains $1.7 \, g$ of ammonia gas. Calculate the following:
$(i)$ Molar mass of ammonia.
$(ii)$ How many moles of ammonia are present in the gas jar?
$(iii)$ How many molecules of ammonia are present in the sample?