Write the molecular formula of ammonia and give the ratio by mass of atoms present.

Write the molecular formula and give the ratio by mass of atoms present in methane.

Calculate the number of moles in $17 \mathrm{g}$ of ${\mathrm{H}}_2{\mathrm{O}}_2$.

Calculate the number of moles in $2.2 \mathrm{g}$ of ${\mathrm{CO}}_2$.

Calculate the number of moles in $16 \mathrm{g}$ of ${\mathrm{SO}}_2$.

Calculate the number of moles in $2.4 \mathrm{g}$ of ${\mathrm{O}}_3$.