Freezing point depression

[D.D.S.]

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Question about freezing point...

Find the freezing point of a solution with 23g ethanol dissolved in 250g water with Kf = 1.86.

freezing point = (m)(Kf)(i) :::: where i, is the number of particles dissociated (something like that from destroyer).... here would i = 2???

does ethanol in water dissociate? because according to the answer, i=1...

Thanks in advance.

 

[Blackjack21]

Im not 100% sure, but i think the reason ethanol doesnt dissociate is because the hydrocarbons.

 

[schmick]

For ethanol and other nonelectrolytes, i is 1. It would be 2 for NaCl.

 

[bennijai]

i thought the freezing point equation was just:

freezing point=(Kf)(m)...where does 'i' come from?!

 

[predentn]

i thought the freezing point equation was just:

freezing point=(Kf)(m)...where does 'i' come from?!

Van't Hoff factor.

 

[Hysteria24]

Yeah, I’m confused now too. If the solute were to dissociate, wouldn’t it just be reflected in the molality since the moles of solute would be doubled?

 

[jay47]

Well, that is true, but it is easier just to multiply the molality by 2 than make two calculations for the molalities of each ion in solution.

For example, if you had MgCl2, which would dissociate into three ions. Suppose you had 3 moles of it on 1 kg solvent. This would be the calculation- deltaT= (3)[3/1](1.86), much easier than just adding all of the molalities together.

Correct me if I am wrong please.