Question

In a phase diagram, what does critical temperature mean?

a) The highest temperature at which a substance can exist as a gas

b) The lowest temperature at which a substance can exist as a solid

c) The temperature at which all phases coexist

d) The temperature at which a substance becomes supercritical

Answer 1

The critical temperature in a phase diagram is the highest temperature at which a substance can exist as a liquid.

Step-by-step explanation:

The critical temperature (Tc) in a phase diagram refers to the highest temperature at which a substance can exist as a liquid. Above the critical temperature, the molecules have too much kinetic energy for the intermolecular attractive forces to hold them together in a separate liquid phase, and instead, the substance forms a single phase that completely occupies the volume of the container. The critical temperature is a characteristic property of a substance and is influenced by the strength of intermolecular forces.