Question

Which change in state requires that energy be added to the substance?

Answer 1

Heat energy is absorbed to vaporize a liquid because molecules which are held together by intermolecular forces in the liquid are separated as the gas is formed. Such a separation requires energy. As with melting, the amount of energy needed to vaporize a substance is proportional to the amount of substance present.

hope this helps u

Answer 2

Heat energy is absorbed to vaporize a

liquid because molecules which are held

together by intermolecular forces in the

liquid are separated as the gas is formed.

Such a separation requires energy . As with

melting, the amount of energy needed to

vaporize a substance is proportional to the

amount of substance present.