Question

What is the theoretical yield of carbon dioxide gas on complete combustion of 250 grams of naproxen?

Answer 1

Complete combustion of naproxen takes place in excess of oxygen thus, naproxen is a limiting reactant and amount of carbon dioxide produced from it is theoretical yield of carbon dioxide.

The balanced chemical reaction for combustion of naproxen is as follows:

$C_{14}H_{14}O_{3}+16O_{2}\rightarrow 14CO_{2}+7H_{2}O$

From the balanced chemical reaction, 1 mole of naproxen $C_{14}H_{14}O_{3}$ gives 14 mol of $CO_{2}$.

The mass of naproxen is given 250 g, molar mass is 230.259 g/mol thus, number of moles will be:

$n=\frac{m}{M}=\frac{250 g}{230.259 g/mol}=1.0857 mol$

Thus, number of moles of $CO_{2}$ obtained from 1.0857 mol of naproxen will be:

$n_{CO_{2}}=14\times 1.0857 mol=15.2 mol$

Now, convert this into mass as follows:

$m=n\times M$

Molar mass of $CO_{2}$  is 44 .01 g/mol thus,

$m=15.2 mol\times 44.01 g/mol\approx 669 g$

Thus, theoretical yield of $CO_{2}$ is 669 g.