Calculate the number of grams of glycerol C3H5(OH)3(MW=92.1g/mol) , that must be dissolved in5 520 gm   grams of water to raise the boiling point to 102.000c

Asked by s.ojaswini17 | 6th Feb, 2019, 01:59: AM

Expert Answer:

Given:
 
Molecular Weight of glycerol = 92.1 g/mol
 
We know,
 
ΔT = m× Kf 
 
Where,
 
ΔT = 100 - 102
 
     = 2 °C
 
m = molality of a solution
 
molality space equals space fraction numerator No. space of space moles space of space solute over denominator Wt space of space solvent space in space kg end fraction

space space space space space space space space space space space straight m equals fraction numerator begin display style bevelled fraction numerator Wt space of space solute over denominator Molecular space wt space of space solute end fraction end style over denominator 0.520 end fraction

therefore increment straight T space equals space straight m cross times straight k subscript straight b

space space space space space space space 2 space equals space fraction numerator begin display style bevelled fraction numerator Wt space of space solute over denominator Molecular space wt space of space solute end fraction end style over denominator 0.520 end fraction cross times straight k subscript straight b

straight k subscript straight b space of space straight H subscript 2 straight O space equals space 0.52 space to the power of degree straight C space kg divided by mol

space space space space space 2 space equals fraction numerator begin display style bevelled fraction numerator Wt space of space solute over denominator 92.1 end fraction end style over denominator 0.520 end fraction cross times 0.52

Wt space of space solute space equals space fraction numerator 2 cross times 0.520 cross times 92.1 over denominator 0.52 end fraction
space space space space space space space space space space space space space space space space space space space
space space space space space space space space space space space space space space space space space space space equals 184.2 space straight g space of space straight C subscript 3 straight H subscript 5 open parentheses OH close parentheses subscript 3 space
 
Weight of glycerol is 184.2 g.
 

Answered by Varsha | 6th Feb, 2019, 01:05: PM

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