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

Answer: (A)

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