Question
Data:
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
questions:
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?
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
questions:
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?
Answers
DrBob222
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.
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.