Question12. An unknown compound contains $51.89 \%$ lead, $16.06 \%$ sulfur and $32.05 \%$ oxygen. Mass spec analysis shows that the unknown compound has a molar mass of 798.7 $\mathrm{g} / \mathrm{mol}$. Determine the empirical and molecular formulas of the compound.

Studdy Solution
Determine the molecular formula using the empirical formula and the given molar mass:
$$\text{Molar mass of compound} = 798.7 \, \text{g/mol}$$
$$\text{Ratio} = \frac{798.7}{367.27} \approx 2.175$$
Since the ratio should be a whole number, round to the nearest whole number, which is 2.
Multiply the subscripts in the empirical formula by 2 to get the molecular formula:
Empirical formula: $\text{PbSO}_8$
Molecular formula: $\text{Pb}_2\text{S}_2\text{O}_{16}$