Question

what is the boiling point that contains 3.15 moles of ethylene C2H6O2 and 250.0g of H2O? answer should end in degree's celcius

a) 1.03 C
b) 93.55 C
c) 106.45 C
d) 6.45 C
e) 103.44 C

Answer 1

molality = mols/kg solvent.
Solve for molality.

delta T = Kb*molality
Solve for delta T.

Add delta T + normal boiling point to obtain new boiling point.

Answer 2

3.15 mol / 0.250 kg = 12.6 mol/kg or 12.6 molal
The boiling point of a solution is
Tb = Tb(H2O) + deltaT = 100º + deltaT
deltaT = Kb*m = (0.512deg.kg/mol)(12.6mol/kg)

NOTE: C2H6O2 is not ethylene. It may be
CH3-O-O-CH3 whose solubility could not be 12.6molal. It is a bad question. The solution given gives the most likely *expected* answer.