What is the melting point of a mixture of 2.00 lb of NaCl and 12.00 pounds of ice if exactly half of the ice melts? Assume that all the NaCl disolves in the melted ice and that the van't Hoff factor for resulting solution is 1.44.

Answer 1

6 lbs melted ice x 454 g/lb = ? grams H2O as the solvent.
2 lbs NaCl x 454 = ? grams NaCl.

delta T = i*Kf*m
i = 1.44
Kf = 1.86
You need m to solve for delta T.

mol NaCl = grams NaCl/molar mass NaCl
molality = moles NaCl/kg solvent.
delta T = i*Kf*m
Subtract delta T from 0 C to find melting point.

Answer 2

-3.15

Answer 3

-15.3

Answer 4

-15.280 degrees Celsius

Answer 5

-15.3