Question

Changes of state

Answer 1

Answer: first statement, "At segment T-U, the substance changes from liquid to gas and does not change temperature"

Explanation:

if the segment T-U is flat (not inclined), means that the temperature is not changing. In this case, the heat provided to the substance is being used to overcome the intermolecucular attraction forces, which permits the particles to get more separated and, in such way, the liquid pass to gas phase.

Answer 2

Answer:

Option A

Explanation:

At segment T-U, the substance changes from a liquid to a gas and does not change temperature.

The reason is because latent heat of vaporisation allows for the absorption of heat in the change of state and temperature remains constant until it has fully changed state.