1.00 g of a non-electrolyte solute dissolved in 50 g of benzene lowered the freezing point of benzene by 0.40K. The freezing point depression constant of benzene is 5.12 K kg/mol. Find the molar mass of the solute

 

Asked by rockdeva663 | 17th Apr, 2019, 09:58: AM

Expert Answer:

Kf = 5.12 K k/mol
W1 = 50 g
W2 = 1.0 g
ΔTf = 0.4 K
 
increment straight T subscript straight f space equals space straight K subscript straight f space cross times space straight W subscript 2 space cross times fraction numerator 1000 over denominator straight W subscript 1 space cross times straight M subscript 2 space end fraction
straight M subscript 2 space equals space straight K subscript straight f space cross times space straight W subscript 2 space cross times fraction numerator 1000 over denominator straight W subscript 1 space cross times space increment straight T subscript straight f end fraction
straight M subscript 2 space equals space 5.12 space cross times space 1 space cross times fraction numerator 1000 over denominator 50 space cross times space 0.4 end fraction
straight M subscript 2 space equals space 5120 over 20
straight M subscript 2 space equals space 256 space straight g
 
 
 

Answered by Ramandeep | 17th Apr, 2019, 10:41: AM