Question

A 5 mole sample of liquid acetone is converted to a gas at 75.0°C. If 628 J are required to raise the temperature of the liquid to the boiling point, 15.600 kJ are required to evaporate the liquid, and 712 J are required to raise the final temperature to 75.0°C, what is the total energy required for the conversion?

Answer 1

The total energy required for this conversion is equivalent to the sum of the energies that are used. There are three steps:

1) Heating of liquid acetone
This used 628 J

2) Evaporation of acetone
This used 15.6 kJ or 15,600 J

3) Heating of acetone vapors
This used 712 J

Adding these quantities,

Total energy = 628 + 15,600 + 712

The total energy required was 16940 Joules of 16.94 kJ