# How many grams are in 0.02 moles of beryllium iodide, "Bel"_2 ?

Feb 13, 2018

$\text{5 g}$

#### Explanation:

All you need to do here is to use a conversion factor that can take you from grams of beryllium iodide to moles of beryllium iodide.

As you know, the molar mass of a compound tells you the mass of exactly $1$ mole of that compound. Beryllium iodide has a molar mass of ${\text{262.821 g mol}}^{- 1}$, which means that $1$ mole of beryllium iodide has a mass of $\text{262.821 g}$.

So you can say that you have

${\text{262.821 g mol"^(-1) = "262.821 g"/"1 mole BeI}}_{2}$

To find the mass of $0.02$ moles of beryllium iodide, simply multiply the number of moles by the molar mass in conversion factor form.

$0.02 \textcolor{red}{\cancel{\textcolor{b l a c k}{\text{moles BeI"_2))) * "262.821 g"/(1color(red)(cancel(color(black)("mole BeI"_2)))) = color(darkgreen)(ul(color(black)("5 g}}}}$

The answer must be rounded to one significant figure, the number of significant figures you have for the number of moles present in your sample.