Question

How many liters of anti-freeze ethylene glycol [Ch2(OH)Ch2(OH)] would you add to a car radiator containing 6.50 L of water if the coldest winter temperature in the area is -20 degree celcius? Calculate the boiling point of of this mixture. The density of th ethylene glycol is 1.11 g/ml. The k (f) of water is 1.86 /m and k(b) of water is 0.52 C/m. Please advise with steps included, thanks.

Answer 1

delta Tf = 0 -(-20) = 20 oC

Kf = 1.86 oC / m

delta Tf   = Kf x molality

20 = 1.86 x molality

molality = 10.75 m

molality = moles of solute / mass of solvent

density of water = 1 g / mL

so mass of water = volume of water

10.75 = moles of solute / 6.50

69.89 = moles

mass of glycol = moles x molar mass

                         = 69.89 x 62

                          = 4333 g

mass of anti -freeze = 4333 g

delta Tb = Kb x molality

Tb - 100 = 0.52 x 10.75

Tb = 105.6 oC

boiling point = 105.6^oC