Calculate the amount (in moles) for the following mass:

$58.8 \mathrm{g}$ of nitric acid ${\mathrm{HNO}}_3$ (calculate ${\mathrm{M}}_{\mathrm{r}}$).

Calculate the concentration, in $\mathrm{mol} {\mathrm{dm}}^{-3}$, of the following:

$0.20 \mathrm{mol}$ of nitric acid, ${\mathrm{HNO}}_3$, dissolved in water to make a $0.50 {\mathrm{dm}}^3$ solution.

Calculate the concentration, in $\mathrm{mol} {\mathrm{dm}}^{-3}$, of the following:

$8.00 \mathrm{g}$ of sodium hydroxide, $\mathrm{NaOH}$, dissolved in water to make a $0.80 {\mathrm{dm}}^3$ solution.

Calculate the concentration, in $\mathrm{mol} {\mathrm{dm}}^{-3}$, of the following:

$0.45 \mathrm{mol}$ of sulphuric acid, ${\mathrm{H}}_2{\mathrm{SO}}_4$, dissolved in water to make a $0.75 {\mathrm{dm}}^3$ solution.

Calculate the concentration, in $\mathrm{mol} {\mathrm{dm}}^{-3}$, of the following:

$6.80 \mathrm{g}$ of ammonia, ${\mathrm{NH}}_3$, dissolved in water to make a $800 {\mathrm{cm}}^3$ solution.

Two students are each asked to measure out three $9.5 \mathrm{g}$ samples of a reactant. When their teacher checked their results, she found the following:

Comment on the level of accuracy and precision of both sets of data.