Question

A 50/50 blend of engine coolant and water (by volume) is usually used in an automobile\'s engine cooling system. If your car\'s cooling system holds 6.00 gallons, what is the boiling point of the solution? Make the following assumptions in your calculation: at normal filling conditions, the densities of engine coolant and water are 1.11 g/mL and 0.998 g/mL respectively. Assume that the engine coolant is pure ethylene glycol (HOCH2CH2OH), which is non-ionizing and non-volatile, and that the pressure remains constant at 1.00 atm. Also, you\'ll need to look up the boiling-point elevation constant for water.

Solvent	Formula	Kf value* (°C/m)	Normal freezing point (°C)	Kb value (°C/m)	Normal boiling point (°C)
water	H2O	1.86	0.00	0.512	100.00
benzene	C6H6	5.12	5.49	2.53	80.1
cyclohexane	C6H12	20.8	6.59	2.92	80.7
ethanol	C2H6O	1.99	–117.3	1.22	78.4
carbon tetrachloride	CCl4	29.8	–22.9	5.03	76.8
camphor	C10H16O	37.8	176

Answer 1

Let us consider 1 ltr of solution.

Volume of coolant=500 ml

Mass of coolant=500*1.11=555 g

Moles of coolant=Mass of coolant/molecular wt=555/62=8.952 moles

Mass of water=500*.998=499 g=0.499 kg

Molality of water= moles of solute/Mass of solvent of in kg=8.952/0.499=17.94 m

Boiling point of blend=Normal boiling point+k_b*molality

                                                =100.00+0.512*17.94=109.19 ℃