Question

What does the line in a solubility chart mean?

Answer 1

The line in a solubility chart shows, for the substance it is referring to, the solubility of that substance at a specific temperature (or whatever the independent variable is on the chart).

(image from www.sciencegeek.net)

For example, in the above graph, the purple ( `Ce_2 (SO_4)_3` ) line, when at `10^o C`, has a solubility of 10 grams of salt in 100 grams of `H_2O`.