Question

(i) Calculate the volume of air needed for the combustion of 1 kg of carbon?
(ii) Calculate the volume of carbon dioxide obtained at S.T.P by heating 8.4 g of sodium carbonate.
${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}\to {\text{Na}}_{\text{2}}{\text{O + CO}}_{\text{2}}$

Answer 1

$\left(i\right)$ $C+O_2⟶C{O}_2$

$\frac{1000}{12}$ $\frac{1000}{12}$

$\frac{1000}{12}$

$\frac{1}{12}$ $kg$ $moles$ of $O_2$ are needed.

$O_2$ consitutes $21\%$ of air.

Total moles of air be $x$

$⟹x\times 0.21=\frac{1}{12}$

$⟹x=0.396$ $moles$

Volume occupied by air $=0.396\times 22.4=8.8$ $L$

$\left(ii\right)$ Moles of Sodium carbonate $=\frac{8.4}{106}=0.08$ $moles$

$N{a}_{2}C{O}_3⟶N{a}_{2}O+C{O}_2$

$0.08$

$0.08$ $0.08$

Volume of $C{O}_2$ at STP $=0.08\times 22.4=1.792$ $Litres$