How to calculate solubility?

Question

I am doing a prac report on obtaining a solubility curve for KClO3

This is the table i have so far...

Mass of KClO3 Volume of water mL Temp *C

4 10 82.5

4 12.5 72.5

4 15 70

4 17.5 62

4 20 52

So that's what i have so far and I have to work out the solubility for each of them, how to i do this? Is there a formula for it? and also if it became a supersaturated solution would effect would it have on the results and how do you overcome such errors?

Thanks for any help

Answer 1

First, you need to convert all of your volumes to 100mL.  Use the equation:

volume * x = 100

solve for x

Then, multiply your mass of KClO3 by x

mass * x = y

The solubility would then be y grams/100 grams of water at the given temperature.  So, for your first set of data:

10mL * x = 100mL

x = 10

4g * 10 = 40g

solubility = 40g/100g water at 82.5 C

Use this method for the rest of your data.  If a solution is supersaturated, it means there's more dissolved solute than there really should be, so your determined solubility of the supersaturated solution would be too high.