Solutions

Solutions

Question

Ethylene glycol is used as an antifreeze in a cold climate. Mass of ethylene glycol which should be added to 4 kg of water to prevent it form freezing at - 6° C will be : (Kf for water = 1.86 K kg mol-1, and molar mass of ethylene glycol = 62g mol-1)

  • 804.32 g

  • 204.30 g 

  • 400.00 g

  • 304.60 g

Answer

A.

804.32 g

ΔTf = iKfm
ΔTf = 6ºC
w1 = mass of ethylene glycol in grams
w2 = mass of solvent (H2O) in grams= 4000g
m1 = Molar mass of ethylene glycol = 62 g
i = 1
i is van't off factor
increment straight T subscript straight f space equals space fraction numerator 1000 space straight K subscript straight f space straight w subscript 1 space left parenthesis straight i right parenthesis over denominator straight m subscript 1 straight w subscript 2 end fraction
therefore space 6 space equals space fraction numerator 1000 space straight x space 1.86 space straight x space straight w subscript 1 space straight x space 1 over denominator 62 space straight x space 4000 end fraction
space straight w subscript 1 space equals space 804 space straight g

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