Question

The mass of 100 litres of sulphur dioxide at STP is 144 g.

• A. True
• B. False

Answer 1

The correct option is B

False

Given volume of sulphur dioxide = 100 litres

Molar volume at STP (litres) = 22.4 L

In case of gases at STP,

Number of moles = $\frac{\text{Volume at STP (litres)}}{\text{Molar volume at STP (litres)}}$ .... (i)

Substituting the values of volume at STP and molar volume at STP in equation (i) we have
Number of moles = $\frac{100}{22.4}$
Hence, number of moles = 4.5

Mass of sulphur dioxide = Number of Moles x Gram molecular mass of Sulphur dioxide ($S{O}_2$) ...(ii)
Gram molecular mass of $S{O}_2$ = Atomic mass of sulphur + (2 x Atomic mass of Oxygen)
Gram molecular mass of $S{O}_2$ = 32 + 2 x 1 = 64 g
Substituting the value of gram molecular mass $S{O}_2$ and number of moles in equation (ii) we get:
The mass of 100 litres of sulphur dioxide at STP = 4.5 x 64 g
$\therefore$ The mass of 100 litres of sulphur dioxide at STP = 288 g.