Question

Write the molecular formula of each of the following compound whose:

(a) empirical formula$={\mathrm{C}}_2{\mathrm{H}}_4\mathrm{O}$, molecular weight$=132$

Answer 1

Given information.

• Empirical formula$={\mathrm{C}}_2{\mathrm{H}}_4\mathrm{O}$
• Molecular weight$=132$

Calculation of empirical formula weight

• The empirical formula weight for ${\mathrm{C}}_2{\mathrm{H}}_4\mathrm{O}$ is calculated as follows:

$\begin{array}{rcl}\mathrm{Empirical}\mathrm{formula}\mathrm{weight}& =& \left(12\times 2+1\times 4+16\right)\mathrm{g}\\ & =& 44\mathrm{g}\end{array}$

Calculation of value of $\mathit{n}$

• Determine the value of $n$ as follows:

$\begin{array}{rcl}n& =& \frac{\mathrm{Molecular}\mathrm{weight}}{\mathrm{Empirical}\mathrm{formula}\mathrm{weight}}\\ & =& \frac{132}{44}\\ & =& 3\end{array}$

Determination of the molecular formula

• The molecular formula is determined as follows:

$\begin{array}{rcl}\mathrm{Molecular}\mathrm{formula}& =& {\left(\mathrm{Empirical}\mathrm{formula}\right)}_n\\ & =& {\left({\mathrm{C}}_2{\mathrm{H}}_4\mathrm{O}\right)}_3\\ & =& {\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_3\end{array}$

Therefore, the molecular formula of the compound is ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_3$.