Question

At 100$^\circ$C and 1 atm. if the density of liquid water is 1.0 g $cm^{-3}$ and that of water vapour is 0.0006 g $cm^{-3}$, then the volume occupied by water molecules in 1 litre of steam at that temperature

• A. 6$cm^3$
• B. 60 $cm^3$
• C. 0.6 $cm^3$
• D. 0.06 $cm^3$

Answer 1

Answer: (C)

0.6 $cm^3$

Answer 2

1L = 1000 mL = 1000 $cm^3$
Mass = Density $\times$ volume
= (0.0006 g $cm^{-3}) \times$ (1000 $cm^3$)
= 0.6 g
18 g of water = 18 $cm^3$
$\therefore$ 0.6 g of water = 0.6 $cm^3$
$\therefore$ 0.6 g of water = 0.6 $cm^3$
Actual volume occupied by molecules = 0.6 $cm^3$