Phaes Diagram Lesson

What are Phase Diagrams and How do we use them?

Regents Question Practice

Multiple Choice

The graph below shows a compound being cooled, beginning in the liquid phase.

Which statement describes the average kinetic energy and the potential energy between minute 2 and minute 6?

• (1) Average kinetic energy and potential energy both decrease.

• (2) Average kinetic energy and potential energy both remain constant.

• (3) Average kinetic energy remains constant and potential energy increases.

• (4) Average kinetic energy remains constant and potential energy decreases.

Multiple Choice

Given the cooling curve for a substance in the picture:

During which intervals is the potential energy decreasing while the average kinetic energy remains constant?

• (1) BC and AB

• (2) BC and DE

• (3) EF and AB

• (4) EF and DE

Multiple Choice

The cooling curve below represents the uniform cooling of a substance, starting at a temperature above its boiling point.

During which time interval does the substance exist as both a liquid and a solid?

• (1) min 2 to min 4

• (2) min 4 to min 5

• (3) min 5 to min 7

• (4) min 7 to min 9

Multiple Choice

The heating curve below represents a sample of a substance starting as a solid below its melting point and being heated over a period of time.

Which statement describes the energy of the particles in this sample during interval DE?

• (1) Both potential energy and average kinetic energy increase.

• (2) Both potential energy and average kinetic energy decrease.

• (3) Potential energy increases and average kinetic energy remains the same.

• (4) Potential energy remains the same and average kinetic energy increases

Multiple Choice

The graph below represents the uniform heating of a sample of a substance starting as a solid below its melting point.

Which statement describes what happens to the energy of the particles of the sample during time interval DE?

• (1) Average kinetic energy increases, and potential energy remains the same.

• (2) Average kinetic energy decreases, and potential energy remains the same.

• (3) Average kinetic energy remains the same, and potential energy increases.

• (4) Average kinetic energy remains the same, and potential energy decreases.