Question

The number of molecules present in 0.036gm of water

Answer 1

Explanation:

$\bold{Molar \: Mass \: of \: H_2O -} \\ H_2O \\ 1 \times 2 + 16 \\ = 18 \\ \\ \fbox\bold{mole(n) = \frac{Mass}{Gram \: molecular \: mass} } \\ \\ \bold{n_{H_2O}} = \frac{0.036}{18} \\ \bold{n_{H_2O}} = 0.002 \\ \\ Now, \\ \fbox\bold{ Number \: of \: molecules = n \times N_{a}} \\ \\ 0.002 \times 6.022 \times {10}^{23} \\ = 0.012044 \times 10 {}^{23} \\ = 1.2044 \times {10}^{21} \\ \\ Hence, \\ Number \: of \: molecule \: present \: in \: \\ 0.036 \: g \: of \: Water \: is \: \bold{1.2044 \times {10}^{21} }$