# What volume of ethanol has a density mass of 15.5 grams?

You mean to ask what volume of ethanol has a mass of $15.5 \cdot g$.
We have $\text{Density, "rho="Mass"/"Volume}$
And thus, $\text{Volume}$ $=$ $\frac{\text{Mass}}{\rho}$ $=$ $\frac{15.5 \cdot g}{0.789 \cdot g \cdot c {m}^{-} 3}$
$\cong$ $20 \cdot c {m}^{3}$