Question

The heat of vaporization of carbon tetrachloride (CCl4) is 197.8 J/g. How much energy is absorbed by 1.35 mol CCl4 when it vaporizes at its boiling point?

Answer 1

41.1 kJ

Question:

The heat of vaporization of carbon tetrachloride (CCl4) is 197.8 J/g. How much energy is absorbed by 1.35 mol CCl4 when it vaporizes at its boiling point?

Answer 2

As a substance vaporizes at its boiling point, the temperature of the system is constant while the phase change is happening. The heat involved is called the latent heat of vaporization and this is constant at a certain temperature and pressure. For CCl4, it is 197.8 J/g. We calculate the total heat that is absorbed as follows:

Heat = mH
Heat = 1.35 mol CCl4 ( 153.81 g / 1 mol ) ( 197.8 J/g )
Heat = 46548.14 J