Question

Consider the following phase diagram. What phases arepresent at points Athrough H? Identify the triple point,normal boiling point, normal freezing point, and criticalpoint. Which phase is denser, solid or liquid?

Short answer

Point	Description
A	Solid-phase region
B	Liquid-phase region
C	Gas-phase region
D	Normal Freezingng point
E	Triple point
F	Normal Boiling point
G	Critical point
H	Supercritical fluid point

Step-by-step solution

The phases present in the given phase diagram

From points A through H, there are three phases included. The phases in the above phase diagram are solid, liquid, and gas.

If we see from point A to H, the phase change is given as

Region	Phase change
A to B	Solid to liquid
B to C	Liquid to gas
C to D	No change
D to E	Sublimation curve
E to F	Vapour pressure curve
F to G	Vapour pressure curve
G to H	Supercritical fluid

The points from the phase diagram

The points are described as follows-

Point	Description
A	Solid-phase region
B	Liquid-phase region
C	Gas-phase region
D	Normal Freezing point
E	Triple point
F	Normal Boiling point
G	Critical point
H	Supercritical fluid point

The solid phase is denser than the liquid as the slope of the solid-liquid equilibrium curve is positive. If the pressure rises, the molecules become more close to the volume of the sample decreases.