Calculate first the number of moles of ethylene glycol by dividing the mass by the molar mass. n = (6.21 g ethylene glycol) / 62.1 g/mol n = 0.1 mol Then, calculate the molality by dividing the number of moles by the mass of water (in kg). m = 0.1 mol/ (0.025 kg) = 4m Then, use the equation, Tb,f = Tb,i + (kb)(m) Substituting the known values, Tb,f = 100°C + (0.512°C.kg/mol)(4 mol/kg) <em>Tb,f = 102.048°C</em>