posted by Tina .
freezing point of pure cyclohexane: 6.0 degrees celcius
Freezing point of unknown soluton: 1.6 degrees celcius
weight of cyclohexane: 40.0231g=0.0400231 kg
weight of unknown solute: 0.4872 g
K_f_ of cyclohexane: -20.00 degrees Celciusx kg/mole
1. what is the change in freezing point of cyclohexane?
2. what is the molarity of the solution?
3. what is the moleculr weight of the unknown solute?
1. normal freezing point - freezing point soln = change.
2. I think you want molality and not molarity. delta T = Kf*m. Solve for m = molality.
3. molality = moles/kg solvent
Solve for moles.
Then moles = grams/molar mass. Solve for molar mass.