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Topic: depression of freezingpoint  (Read 3746 times)

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Offline diablo

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depression of freezingpoint
« on: April 29, 2007, 06:40:48 AM »
Hi, got another prob here:

An antifreeze protein ( 17.000 Da) was found in concentration 10g/L in the serum of an antartic fish
Calculate the expectet depression of the freezing point...

I got the forumlar : dT = ( RxTm2x xs) / Lf

Tm.. Melting point of pure water = 273,15K
Lf.... latent heat of fusion = 6,02kJ /mol
xs.... Mole fraction of the solute in the solution

The right answer = 0,0011 (in my biophysicsbook ); but i dont know how to get this value

I calculatet mole of fraction : 10g/L divided by 17000 g/mol , and if i put this in equation i don't get this value.... anyone familiar with this formular or can help me to solve this prob?^^

thx diabloooo

Offline Yggdrasil

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Re: depression of freezingpoint
« Reply #1 on: April 29, 2007, 02:18:50 PM »
http://en.wikipedia.org/wiki/Freezing_point_depression

I think you may be confusing which equations to use.

Offline diablo

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Re: depression of freezingpoint
« Reply #2 on: April 29, 2007, 03:51:27 PM »
thx for your help --> y the link is a bit confusing^^

actually i already got it --> formular above is ok ; mol fraction is calculated in proportio to water
(nprotein / (nprotein)+(nwater) ) then it's correct ;D

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