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posted by  sampson32 on 9/12/2008 1:47:03 AM  |  status: Closed  

Calculate molar mass of solute.

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Question Details:
A solution that contains 55g of ascorbic acid in 250g of water freezes at -2.34oC. Calculate the molar mass (g/mol) of the solute. Kf of water is 1.86oC/m

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posted by Jesley on 9/12/2008 2:28:34 AM  |  status: Live
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sampson32's comment:
"Thanks for your help"
Response Details:
 
by using the formula of freezing point depression
                        ΔTf =Tf0  -Tf  =Kf m
where, Tf0 =freezing point of pure solvent =0 oC
Tf =freezing point of solution =-2.34oC
Kf = freezing point depression constant =1.86oC/m
m= concentration of solute in molality =?
first determine 'm' using the formula
 
molality  =moles of solute/mass of solvent in kg
moles of solute = m*(0.250kg)
                         
molar mass ,Mm = mass/moles
                              
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