# How many moles are there in 100 g of copper oxide, CuO?

$100 \cdot g \text{ cupric oxide}$ constitutes a bit over $1 \cdot m o l$.
$\text{Number of moles}$ $=$ $\text{Mass"/"Molar mass}$ $=$
$\frac{100 \cdot \cancel{g}}{79.95 \cdot \cancel{g} \cdot m o {l}^{-} 1}$ $=$ ??mol.