Question

Determination of sulfur by combustion analysis produces a mixture of ${\mathbf{SO}}_{\mathbf{2}}$and ${\mathbf{SO}}_{\mathbf{3}}$ that can be passed through ${\mathbf{H}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{2}}$to convert both into ${\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}$, which is titrated with standard base. When 6.123m g of a substance were burned, the ${\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}$ required 3.01mL of0.010576MNaOHfor titration. Find wt% sulfur in the sample.

Short answer

The weight percent of sulfur in the sample is 0.124 .

Step-by-step solution

Derfining the weight percent.

The Weight Percentage is simply the ratio of a solute's mass to the mass of a solution multiplied by 100. The Weight Percentageis also referred to as the Mass Percentage.

$\mathrm{Percentbyweight}=\frac{\mathrm{gram}\mathrm{of}\mathrm{solute}}{100\mathrm{g}\mathrm{of}\mathrm{solution}}$$\mathrm{Percentbyweight}=\frac{\mathrm{gram}\mathrm{of}\mathrm{solute}}{100\mathrm{g}\mathrm{of}\mathrm{solution}}$

Determining the moles of NaOH and H2So$

Here of were required for titration of when of a substance were burned. We need to find the weight percent of sulfur in the sample.

Consider the following reaction:

$$\begin{gathered} {\mathrm{H}}_2{\mathrm{SO}}_4+2\mathrm{NaOH}\to 2{\mathrm{H}}_2\mathrm{O}+{\mathrm{Na}}_2{\mathrm{SO}}_4 \\ \mathrm{n}\left(\mathrm{NaOH}\right)=\mathrm{c}\times \mathrm{V} \\ \mathrm{n}\left(\mathrm{NaOH}\right)=0.01576\mathrm{M}\times 3.01\times {10}^{-3}\mathrm{L} \\ \mathrm{n}\left(\mathrm{NaOH}\right)=4.744\times {10}^{-5}\mathrm{mol} \\ \mathrm{n}\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)=2.372\times {10}^{-5}\mathrm{mol} \end{gathered}$$

Calculating the weight percent.

Then we will find the weight percent of sulfur in the sample:

$$\begin{gathered} \mathrm{wt}\%=\frac{\mathrm{m}\left(\mathrm{S}\right)}{\mathrm{m}\left(\mathrm{sample}\right)} \\ \mathrm{wt}\%=\frac{0.7607\mathrm{mg}}{6.123\mathrm{mg}} \\ \mathrm{wt}\%=0.124 \end{gathered}$$

Therefore the weight percent of sulfur in the sample is 0.124 .