Phase Changes

Question 1

What is a triple point on phase diagrams?

Answer 1

Triple points shows conditions at which three different phases can coexist

The phase diagram of water includes a triple point, which represents the unique combination of temperature and pressure where solid, liquid, and gaseous water can all exist together in stable equilibrium.

Question 2

What does the heat of vaporization measure?

Answer 2

The energy required to change a liquid to a vapour at constant temperature and pressure

The heat of vaporization is generally greater than the heat of fusion, as breaking intermolecular forces to form a gas requires more energy than forming a liquid.

Question 3

What does the** heat of fusion** measure?

Answer 3

The energy required to change a solid to a liquid at constant temperature and pressure

The heat of fusion is lower than the heat of vaporization, as intermolecular forces are not completely broken when transitioning from solid to liquid.

Question 4

What does a horizontal line symbolize on a heating curve?

Answer 4

A phase change

During a plateau, the temperature remains constant while energy is used to change the state of the matter, as melting or vaporization.

Question 5

What happens at the liquid–vapor critical point of a phase diagram?

Answer 5

There is no distinction between liquid and gas

The critical point shows the conditions, for example temperature and pressure, under which a liquid and its vapor can coexist.