Question

 

Points A to G are located on the phase diagram of water. Which of the following statements are correct regarding navigation from one point to another across the phase diagram?

CHECK ALL THAT APPLY.

 

Check all that apply.

	Moving from point A to point C, the temperature increases.
	To move from point D to point F, you must decrease both the temperature and the pressure.
	At point E, the temperature is less than 0%u2218C.
	To move from the point G to point F, you must increase both the temperature and the pressure.
	To move from point C to point D, you must decrease only the pressure.
	To move from point G to point B, you must increase the temperature.

Answer 1

Concepts and reason

In the given phase diagram, move along the paths given and check the direction in which the pressure and temperature move on their respective axis. Decide the correct statement accordingly.

Fundamentals

Phase diagram is a graphical representation of variation of temperature with pressure for various phases of a substance. The graph has temperature on x-axis and pressure on y-axis.

Consider the phase diagram for a one component system given below:

In the given phase diagram,

Point A represents the triple point, where all the three phases exist together.

At point D only solid phase exists.

At point E only liquid phase exists.

At point F only gas phase exists.

Line AC represents phase transition from solid to liquid and vice versa at different temperatures and pressure. Therefore, this line represents the melting and freezing process.

Line AB represents phase transition from gas to liquid and vice versa at different temperatures and pressure. Therefore, this line represents the vaporization and condensation process.

Line AO represents phase transition from solid to gas and vice versa at different temperatures and pressure. Therefore, this line represents the sublimation and deposition process.

At and , the substance exists in solid phase at point D.

Consider the phase diagram for water given below:

In process 1, temperature increases in going from point A to point C.

Point E lies left to the point, thus it has temperature lower than .

In process 4, temperature and pressure increase in going from point G to point F.

In process 2, moving from point C to point D only pressure decreases.

Consider the phase diagram for water given below:

In process 3, temperature decreases in going from point G to point B.

In process 5, moving from point D to point F pressure decreases and temperature increases.

Ans:

The correct statements are:

Moving from point A to point C, the temperature increases.

At point E, the temperature is less than .

To move from the point G to point F, you must increase both the temperature and the pressure.

To move from point C to point D, you must decrease only the pressure.

The incorrect statements are:

To move from point D to point F, you must decrease both the temperature and the pressure.

To move from point G to point B, you must increase the temperature.