Answer:
4.94°C, the temperature for freezing the solution
Explanation:
Freezing point depression to solve this.
Formula = T° freezing pure solvent - T° freezing solution = Kf . m
With the data given, let's determine m (molality)
Molality → mol/kg (moles of solute in 1kg of solvent)
We need to convert the 344 g to kg → 344 g . 1kg/1000 g = 0.344 kg
Let's determine the moles of solute (naphtalene)
5 g / 128 g/mol = 0.039 mol
Molality → 0.039 mol / 0.344 kg → 0.113
Let's go back to the formula:
5.5°C - T° freezing of solution = 4.90°C /m. 0.113 m
T° freezing of solution = - ( 4.90°C /m. 0.113 m - 5.5°C)
T° freezing of solution = 4.94 °C
