# How much potassium nitrate do you think could dissolve in 100 mL of water at 60°C?

Jun 19, 2017

About $\text{110 g}$.

#### Explanation:

Your tool of choice here will be the solubility graph for potassium nitrate, ${\text{KNO}}_{3}$, in water. The solubility graph is a very useful tool because it tells you the amount of potassium nitrate that can be dissolved per $\text{100 mL}$ of water in order to have a saturated solution of potassium nitrate at a given temperature.

In order to find the solubility of the salt at ${60}^{\circ} \text{C}$, start from the ${60}^{\circ} \text{C}$ mark on the graph and move up until you intersect the curve. At the point of intersection, move left until you intersect the $y$ axis and read off the value that you land on.

In this case, you can estimate that the solubility of potassium nitrate in water at ${60}^{\circ} \text{C}$ is equal to about

$\textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{\text{solubility " ~~ " 110 g / 100 mL water}}}}$

This tells you that a saturated solution of potassium nitrate will hold about $\text{110 g}$ of dissolved salt, i.e. of dissociated salt, per $\text{100 mL}$ of water at ${60}^{\circ} \text{C}$.