Question

Calculate the volume of 340 g of ${\text{NH}}_3$ at STP.

Answer 1

Given mass of ammonia (${\text{NH}}_3)$ = 340 g
Molar volume of ${\text{NH}}_3$ at STP (in litres) = 22.4 L
Gram molecular mass of ${\text{NH}}_3$ = 17 g

Number of moles = $\frac{\text{Given mass}}{\text{Gram molecular mass}}$
$\therefore$ Number of moles of ${\text{NH}}_3$ = $\frac{340}{\text{17}}$ = 20 mol

In case of gases at STP,
1 mole of ${\text{NH}}_3$ occupies 22.4 L
$\therefore$ Volume occupied by 20 moles of ${\text{NH}}_3$ at STP = 22.4 $\times$ 20 = 448 L