Boiling Point Elevation and Freezing Point Depression

[IAmLegendToo]

Question 1: Cyclohexane has a freezing point of 6.50C and a Kf of 20.0C/m. What is the freezing point of a solution made by dissolving 0.925 g of biphenyl (C12H10) in 25.0 g of cyclohexane?

Question 2: Paradichlorobenzene, C6H4Cl2, is a component of mothballs. A solution of 2.00g in 22.5g of cyclohexane boils at 82.39C. The boiling point of pure cyclohexane is 80.70C. Calculate Kb for cyclohexane.

Not a clue where to start for either of these. Any help? Push in right direction? Something? lol

Thanks in advance for any help.

[IAmLegendToo]

I'm thinking Part B's answer is:

Kb = 2.73 C/m

EDIT:

Tried it. Again, same as another problem. Rounding error, yet doesn't state SFs wanted. Crappy program. Hmm.

[IAmLegendToo]

Solved.

Answer was 2.79 C/m.

Went ahead and did everything without ANY rounding. Came to 2.794 and several other numbers. So decided to pick 2.79. Was correct.