# How many total moles of KNO_3 must be dissolved in water to make 1.5 liters of a 2.0 M solution?

$\text{Concentration}$ $=$ $\text{Amount of substance (mol)"/"Volume of solution (L)}$
Given $c$ $=$ $\frac{n}{V}$; $n$ $=$ $C \times V$
So $n$ $=$ $2.0 \cdot m o l \cdot \cancel{{L}^{-} 1} \times 1.5 \cdot \cancel{L}$ $=$ $3.0 \cdot m o l$