# How do you calculate the number of moles of potassium hydroxide that must be dissolved to make the following solution: 500 cm^3 of 1 mol/dm^3?

Sep 20, 2016

We use the relationship, $\text{Concentration}$ $=$ $\text{Moles of solute"/"Volume of solution}$. $0.500 \cdot m o l$ $K O H$ are required.
We are given that $\text{Concentration}$ $=$ $1 \cdot m o l \cdot {\mathrm{dm}}^{-} 3$, and that the volume of this solution is $500 \cdot c {m}^{3}$ $=$ $0.500 \cdot {\mathrm{dm}}^{3}$.
Thus $\text{moles of solute}$ $=$ $\text{concentration "xx" volume}$ $=$ $1 \cdot m o l \cdot \cancel{{\mathrm{dm}}^{-} 3} \times 0.500 \cdot \cancel{{\mathrm{dm}}^{3}}$ $=$ $0.500 \cdot m o l$.
What is the mass of the $K O H$ used here?