Question

Tetrasilane $\left({\mathbf{Si}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{10}}\right)$ is a liquid with a density of$\mathbf{0}\mathbf{.}\mathbf{825}\mathbf{g}\mathbf{/}{\mathbf{cm}}^{\mathbf{3}}$. It react with oxygen to give silica$\left({\mathbf{SiO}}_{\mathbf{2}}\right)$and water. Calculate the mass silica that would form it $\mathbf{25}{\mathbf{cm}}^{\mathbf{3}}$tetrasilane reacted completely with excess oxygen.

Short answer

The mass of silica formed in the reaction is 40.9 g.

Step-by-step solution

Calculating the mass of tetrasilane

Volume of tetrasilane =$25c{m}^3$

Density of disilane =$0.825g/c{m}^3$

The mass of tetrasilane is calculated as:

$\mathbf{Mass}\mathbf{=}\mathbf{density}\mathbf{\times }\mathbf{volume}$

$$\begin{gathered} =0.825g/c{m}^3\times 25.0c{m}^3 \\ =20.625g \end{gathered}$$

Calculating the mass of silica

From the question, we get a balanced equation as:

$\mathbf{2}{\mathbf{Si}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{10}}\mathbf{+}\mathbf{13}{\mathbf{O}}_{\mathbf{2}}\to \mathbf{8}{\mathbf{SiO}}_{\mathbf{2}}\mathbf{+}\mathbf{10}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$

$$\begin{gathered} {\text{The molar mass of Si}}_{\text{2}}{\text{H}}_{\text{6}}\text{= 62.23g/mol} \\ {\text{The molar mass of SiO}}_{\text{2}}\text{= 60.09g/mol} \end{gathered}$$

2 moles of tetrasilane gives$8Si{O}_2+10H_{2}O$

20.6g of tetrasilane $\to ?$amount of$Si{O}_2$

$$\begin{gathered} Mass=20.6g.S{i}_4{H}_{10}\times \frac{1mol.S{i}_4{H}_{10}}{122.44g.S{i}_4{H}_{10}}\times \frac{4mol.Si{O}_2}{1mol.Si{O}_2}\times \frac{60.09g.Si{O}_2}{1mol.Si{O}_2} \\ Mass=40.9g.Si{O}_2 \end{gathered}$$

Therefore, mass of silica formed in the reaction is 40.9 g.