Solutions Question 246

Question: The molality of a urea solution in which 0.0200 g of urea ( NH2CONH2 ) is added to 0.400 dm3 of water at STP is

Options:

A) 0.555,mol,kg1

B) 5.55×104,mol,kg1

C) 8.33×104,mol,kg1

D) 33.3,mol,kg1

Show Answer

Answer:

Correct Answer: C

Solution:

1,dm3=100,cm3=1,L=1,kg

0.400,dm3 of H2O at STP= 0.400,kg of H2O (Density=1.0 g cm3 ) Moles of urea = 0.020060mol (Molar mass of NH2,CONH2=60gmol1 )

Molality =Moles,of,solut,(urea)kg,of,solvent=0.020/600.400kg

=8.33×104mol,kg1



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