# How many molecules are present in 1.0 x 103g of water? (Answer with correct number of sig figs)

Nov 14, 2016

$\text{Number of water molecules}$
$= \frac{1.0 \times {10}^{3} \cdot g}{18.01 \cdot g \cdot m o {l}^{-} 1} \times 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$

#### Explanation:

We use $\text{Avogadro's number}$ $=$ 6.022 xx 10^23 *mol"^-1.

And since the units clearly cancel out we get the answer as a dimensionless number.

I leave it to you to determine the correct number of significant figures.