Drug has heat of melting 25 K jule/mole. Solubility of drug in water is 0.00082 M at 25 C and 0.00144M at 35 C. Find mole fractions x1 and x2 at each temperature.

Answer 1

One liter of water is 1000/18 = 55.6 moles.

They tell you now many moles of the drug are in a liter.

Get the mole fraction from the ratio
(moles of drug)/(moles total)

Answer 2

I know that way. But what is the difference in mole fraction of drugs and solvent (water) at different temp?