# How many molecules are there in 220 grams of CF_4?

Dec 10, 2016

There are $1.5 \times {10}^{24}$ $\text{molecules}$ $\text{in}$ $\text{220 g}$ $\text{CF"_4}$.
Divide the given mass of carbon tetrafluoride by its molar mass. Then multiply times $6.022 \times {10}^{23} \text{molecules/mol}$.
$\text{CF"_4}$ molar mass : $\text{88.005 g/mol}$
(220cancel"g CF"_4)/(88.005cancel"g/mole" "CF"_4)xx(6.022xx10^23"molecules CF"_4)/(1cancel"mol CF"_4)=1.5xx10^24"molecules CF"_4" (rounded to two significant figures)