Question

25. To separate benzene from water, a 850 g aqueous solution of benzene is cooled from
95°C to 3°C, where it is then strained from the water as a solid. How many kilojoules of
heat energy are released by the cooling benzene?

Answer 1

Answer:

132.94 kilo joules

Explanation:

We are given;

• Mass of benzene solution is 850 g
• Temperature change from 95°C to 3° C = 92° C or 92 K

We are required to determine the energy released by the cooling of benzene.

Taking the specific heat capacity of liquid benzene as 1.7 kJ/kg/K

Then we can determine the amount of heat energy released by using the formula;

Heat = Mass × specific heat × change in temperature

        = 0.85 kg × 1.7 kJ/kg/K × 92 K

        = 132.94 kilo joules

Therefore, the heat released by cooling benzene is 132.94 kilo joules