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How do I calculate the kf for cyclohexane (pure solvent)? Also how to calculate the mass...

How do I calculate the kf for cyclohexane (pure solvent)?

Also how to calculate the mass of cyclohexane in the solution (kg)?

Please let me know which information is needed in order to solve for this.

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Answer #1

Molar Mass by Freezing Point Depression:

FREEZING POINT DEPRESSION:

The introduction of a solute to a solvent will decrease the freezing point (temperature) of the solvent.

Thus, ∆ Tf α m

so, ∆ Tf = Kf Xm where Kf is the  freezing point depression constant

for cyclohexane, the freezing point is 6.5 °C and Kf value 20.1°C.kg/mole.

The equation needed:

M2=KfX(W2/ ∆ TfXW1)

M2 = molar mass of solute.

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