# How many moles of helium atoms are in 38.00 g of helium gas?

$9.5 \cdot m o l$
The molar mass of helium is $4.00 \cdot g$.
$\text{Moles of substance}$ $=$ $\text{Mass of substance"/"Molar mass of substance}$
$\frac{38.00 \cdot \cancel{g}}{4.00 \cdot \cancel{g} \cdot m o {l}^{-} 1}$ $=$ ??mol