### Theory:

I. Calculate the percentage of $$S$$ in $$H_2SO_4$$.

Data:

Atomic mass of $$H=1$$

Atomic mass of $$S=32$$

Atomic mass of $$O=16$$

Solution:

$\begin{array}{lll}\mathit{Molecular}\phantom{\rule{0.147em}{0ex}}\mathit{mass}\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}{H}_{2}{\mathit{SO}}_{4}& =& \left(2×1\right)+\left(1×32\right)+\left(4×16\right)\\ & =& 2+32+64\\ & =& 98\phantom{\rule{0.147em}{0ex}}g\end{array}$

$\begin{array}{lll}%\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}S\phantom{\rule{0.147em}{0ex}}\mathit{in}\phantom{\rule{0.147em}{0ex}}{H}_{2}{\mathit{SO}}_{4}& =& \frac{\mathit{Mass}\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}\mathit{sulphur}}{\mathit{Molecular}\phantom{\rule{0.147em}{0ex}}\mathit{mass}\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}{H}_{2}{\mathit{SO}}_{4}}×100\\ & =& \frac{32}{98}×100\\ & =& 32.65\phantom{\rule{0.147em}{0ex}}%\end{array}$

Therefore, the percentage of $$S$$ in $$H_2SO_4=32.65%$$

II. Calculate the percentage of $$O$$ in $$H_2SO_4$$.

Data:

Atomic mass of $$H=1$$

Atomic mass of $$S=32$$

Atomic mass of $$O=16$$

Solution:

$\begin{array}{lll}\mathit{Molecular}\phantom{\rule{0.147em}{0ex}}\mathit{mass}\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}{H}_{2}{\mathit{SO}}_{4}& =& \left(2×1\right)+\left(1×32\right)+\left(4×16\right)\\ & =& 2+32+64\\ & =& 98\phantom{\rule{0.147em}{0ex}}g\end{array}$

$\begin{array}{lll}%\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}O\phantom{\rule{0.147em}{0ex}}\mathit{in}\phantom{\rule{0.147em}{0ex}}{H}_{2}{\mathit{SO}}_{4}& =& \frac{\mathit{Mass}\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}\mathit{oxygen}}{\mathit{Molecular}\phantom{\rule{0.147em}{0ex}}\mathit{mass}\phantom{\rule{0.147em}{0ex}}\mathit{of}\phantom{\rule{0.147em}{0ex}}{H}_{2}{\mathit{SO}}_{4}}×100\\ & =& \frac{16}{98}×100\\ & =& 16.32%\end{array}$

Therefore, the percentage of $$O$$ in $$H_2SO_4=16.32%$$