Can anyone explain this chemistry question?

Question

A solution is made by completely dissolving 90. grams of KNO3(s) in 100. grams of

water in a beaker. The temperature of this solution is 65°C.

65 Determine the total mass of KNO3(s) that settles to the bottom of the beaker when the

original solution is cooled to 15°C.

answer:62 g ± 2 g.

please explain

Answer 1

Look at the solubility curve in your book or at http://www.saskschools.ca/curr_content/c...

Look on the x-axis to find 15ºC,  Extend this line to the slope for KNO3.

Trace this back to the y-axis.  It looks lie the cooridinate is about 27g KNO3.

90g - 27g = 63g

Better measuring than my quick look should be your the 62g.