Question

Determine the number of molecules in water which has weight 50 gms.

• A. $16.7\times {10}^{23}$
• B. $4\times {10}^{24}$
• C. $5\times {10}^{11}$
• D. $4\times {10}^{23}$

Answer 1

The correct option is A

$16.7\times {10}^{23}$

1 mole of $H_{2}O$ has weight = 18 gms

18 g of $H_{2}O$ contains molecule of water $=6.023\times {10}^{23}$

$\therefore$ 50 gms of $H_{2}O$ contains molecules

$=\frac{6.023\times {10}^{23}}{18}\times 50$

$=16.7\times {10}^{23}molecules$