Question

Volume occupied by one molecule of water $(density\, = 1 g\, cm^{-3} )$ is

• A. $9.0 \times 10 ^{-23} cm^3$
• B. $6.023 \times 10 ^{-23} cm^3$
• C. $3.0 \times 10 ^{-23} cm^3$
• D. $5.5 \times 10 ^{-23} cm^3$

Answer 1

Answer: (C)

(c) $1 mole= 6.023 \times 10^{23} molecule$
$18 g = 6.02 \times 10^{23} molecule$
18 g = mass of $6.02 \times 10^{23}$ water molecules
Mass of one water molecule $= \frac {18}{6.023\times 10^{23}} g$
Density $ = 1 \, g \, cm^{-3}$
$Volume = \frac {Mass \, of \, one \, water \, molecule}{Density}$
$= \frac {18}{6.023 \times 10^{23} \times1 } = cm^3$
$\simeq 3.0 x 10^{-23} cm^3$