# How many grams are in 4.500 moles of Li_2O?

Mar 1, 2016

$L {i}_{2} O$ has a molecular mass of $29.88$ $g \cdot m o {l}^{-} 1$
So to get the mass of $4.500$ $m o l$, we simply mulitply the molar mass by the number of moles:
$29.88$ $g \cdot \cancel{m o {l}^{-} 1}$ $\times$ $4.500$ $\cancel{m o l}$ $\approx$ $130 \cdot g$.
Lithium oxide also has the mineral name of anti-fluorite, where fluorite is $C a {F}_{2}$. Given that both materials have the same structure, why is $L {i}_{2} O$ known as antifluorite?