"A sample of 21.50 g of KHT is mixed with 1.000 L of pure water. After stirring the mixture for 30 minutes, there is still solid at the bottom of the container. Calculate the mass of the remaining solid. Use the value of Ksp that you obtained in your experiment."

Question

I have the Ksp value calculated but I would like to know how to approach this problem.

Answer 1

..............KHT ==> K^+ + HT^-
I.............solid.........0.........0
C............solid.........x.........x
E............solid..........x.........x

Ksp = (k^+)(HT^-)
Substitute Ksp and solve for x = solubility in mols/L.
Convert to grams/L. That is how many grams will dissolve. Subtract from 21/50 g to find what did not dissolve. Post your work if you get stuck.

Answer 2

Wow I did this thinking I did it wrong...
After making my table and doing the calculations I ended up with 7.93 g/L from a Ksp of 1.18e-3. Does this sound right?

Answer 3

I don't know. You didn't post the molar mass of KHT.
mols/L KHT = moles x molar mass = grams KHT that dissolved.
21.50-grams dissolved = grams left.