Question

The mass of a molecule of water is

• A. $3\times {10}^{-26}kg$
• B. $3\times {10}^{-25}kg$
• C. $1.5\times {10}^{-26}kg$
• D. $2.5\times {10}^{-26}kg$

Answer 1

The correct option is A $3\times {10}^{-26}kg$

$6\times {10}^{23}$ molecules has mass =18 gm
1 molecules has mass $=\frac{18}{6\times {10}^{23}}=3\times {10}^{-23}gm=3\times {10}^{-26}kg$