Question

Maleic acid is an organic compound composed of 41.39% C, 3.47% H, and the rest oxygen. If 0.129 mol of maleic acid has a mass of 15.0 g, what are the empirical and molecular formulas 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$=M=\frac{19.5}{0.168}=116.07\frac{g}{mol}$

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Let atoms of CC be xx

Let atoms of HH be yy

Let atoms of OO be zz

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

$1\times y=0.0347\times 116.07$

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

$x\approx4x≈4$

$y\approx4y≈4$

$z\approx4z≈4$

Hence molecular formula of maleic acid is $C_4H_4O_4$

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And the empirical formula is CHOCHO