Chemisty...solubility?

Question

The solubility of Potassium Chloride is 37.0g/100g water at 30 degreesC. Its solubility at 70degrees C is 48.3g/100g water.

Calculate:

If 30.0g of KCL were added to 75.0g of water at 30degrees C , would it all disappear? If the temperature were increased to 70 degrees C, would it then all dissolve?

How am I supposed to figure this out? Don't I need a solubility chart?

Answer 1

37.0 : 100 = 30.0 : x

x = mass water in which the salt disappears =  81.1

we have only 75.0 g of water so the salt would not all disappear

in the same way

48.3 : 100 = 30.0 : x

x = 62.1 g of water needed

we have 75.0 g of water so it will all disappear

Answer 2

solubility of KCl in 100g is 37g , in 75g it is 75*37/100=27.75g at 30C. So ,the answer is no

Same calculus at 70C gives 48.3*75/100=36.225g So at 70°, you can dissolveyour KCl

...and you need no chart