Question

Hexachlorophene is used as a disinfectant in germicidal soaps. What mass of hexachlorophene (406.9 g/mol) must be added to 125 g of chloroform to give a solution with a boiling point of 62.60°C? (For chloroform, Kb = 3.63°C/m; boiling point of pure chloroform = 61.20°C)

Answer 1

Answer:

There must be added 19.63 grams of hexachlorophene

Explanation:

Step 1: Data given

hexachlorophene has a molar mass of 406.9 g/mole

mass of chloroform = 125 grams

Boiling point of the solution = 62.60 °C

Kb Chloroform = 3.63 °C*kg/mol

Boiling point chloroform = 61.20 °C

Step 2: Calculate change of temperature

ΔT = 61.20 - 62.60 °C = -1.4 °C

Step 3: Calculate molality

-1,4 °C = mass * Kb

-1.4 °C = m * 3.63 °C/molal

m= 0.386 mol/Kg

Step 4: Calculate number of moles

0.386 mole/kg  =  moles solute / 0.125 Kg

moles solute = 0.386 moles/Kg * 0.125 Kg = 0.04825 moles

Step 5: Calculate mass

mass = 0.04825 moles * 406.9 g/mole =19.63 grams

There must be added 19.63 grams of hexachlorophene