Question

Maleic acid is an organic compound composed of 41.39% C, 3.47% H , and the rest oxygen. If 0.168 mole of maleic acid has a mass of 19.5 g, what are the empirical and molecular fomulas of maleic acid?

Answer 1

Number of moles of maleic acid$=0.168mol =\frac{19.5g}{M\frac{g}{mol}}$

So molar mass of maleic acid$=M=\frac{19.5}{0.168}=116.07\frac{g}{mol}$

Let atoms of $C$ be $x$

Let atoms of $H$ be $y$

Let atoms of $O$ be $z$

$12\times x=0.4139\times116.07$

$1\times y=0.0347\times 116.07$

$16\times z=0.5514\times116.07$

$x\approx4$

$y\approx4$

$z\approx4$

Hence molecular formula of maleic acid is $C_4H_4O_4$

And the empirical formula is $CHO$