Question

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

Answer 1

About `"110 g"`.

Explanation:

Your tool of choice here will be the solubility graph for potassium nitrate, `"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 `"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^@"C"`, start from the `60^@"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^@"C"` is equal to about

`color(darkgreen)(ul(color(black)("solubility " ~~ " 110 g / 100 mL water")))`

This tells you that a saturated solution of potassium nitrate will hold about `"110 g"` of dissolved salt, i.e. of dissociated salt, per `"100 mL"` of water at `60^@"C"`.