Entropy Phase Change Quiz: Test Thermodynamics Concepts

10th Grade

Reviewed by Ekaterina Yukhnovich

Ekaterina Yukhnovich, PhD |

Science Expert

Review Board Member

Ekaterina V. is a physicist and mathematics expert with a PhD in Physics and Mathematics and extensive experience working with advanced secondary and undergraduate-level content. She specializes in combinatorics, applied mathematics, and scientific writing, with a strong focus on accuracy and academic rigor.

, PhD

By Thames

Thames

Community Contributor

Quizzes Created: 10017 | Total Attempts: 9,652,179

| Attempts: 13 | Questions: 20 | Updated: Mar 13, 2026

Share on Facebook Share on Twitter Share on Whatsapp Share on Pinterest Share on Email Copy to Clipboard Embed on your website

Question 1 / 21

🏆 Rank #-- ▾

0 %

0/100

Score 0/100

1. When ice melts to liquid water at the same temperature, the entropy of the water:

Decreases

Increases

Stays exactly the same

Becomes zero

Concept: phase change and microstates. Liquids have more accessible molecular arrangements than solids. That increase in possible microstates raises entropy.

Explanation

Concept: phase change and microstates. Liquids have more accessible molecular arrangements than solids. That increase in possible microstates raises entropy.

Submit

About This Quiz

Entropy Phase Change Quiz: Test Thermodynamics Concepts - Quiz

This assessment explores the principles of entropy and phase changes in thermodynamics. It evaluates understanding of key concepts such as the second law of thermodynamics, energy transfer, and the behavior of materials during phase transitions. This knowledge is essential for students and professionals in physics and engineering, providing a solid... see morefoundation for advanced studies in thermodynamics. see less

2. What first name or nickname would you like us to use?

You may optionally provide this to label your report, leaderboard, or certificate.

2. Vaporisation (liquid → gas) usually causes a larger entropy increase than melting (solid → liquid).

True

False

Concept: gas has far more microstates. Gas molecules have much more freedom of motion and spacing. That creates a larger increase in accessible microstates and entropy.

Explanation

Concept: gas has far more microstates. Gas molecules have much more freedom of motion and spacing. That creates a larger increase in accessible microstates and entropy.

Submit

3. Which process most likely increases entropy the most?

Freezing water

Condensing steam

Evaporating water into vapour

Compressing a gas slowly

Concept: expansion of accessible states. Going to a gas phase greatly increases volume and molecular freedom. That typically produces a large entropy increase.

Explanation

Concept: expansion of accessible states. Going to a gas phase greatly increases volume and molecular freedom. That typically produces a large entropy increase.

Submit

4. The spontaneous spreading of a substance from high concentration to low concentration is called ______.

Concept: diffusion and entropy. Diffusion increases the number of ways particles can be arranged in space. This corresponds to increasing entropy.

Explanation

Concept: diffusion and entropy. Diffusion increases the number of ways particles can be arranged in space. This corresponds to increasing entropy.

Submit

5. Two different gases mixed together have higher entropy than the same gases separated.

True

False

Concept: mixing entropy. Mixing increases the number of arrangements because each gas can occupy the full volume. The mixed state is overwhelmingly more probable.

Explanation

Concept: mixing entropy. Mixing increases the number of arrangements because each gas can occupy the full volume. The mixed state is overwhelmingly more probable.

Submit

6. If you dissolve sugar in water, the entropy of the system generally:

Decreases because sugar 'disappears'

Increases because particles become more dispersed

Stays the same

Must decrease to conserve energy

Concept: dissolving as dispersal. Dissolving spreads solute particles through the solvent. This increases the number of microstates available.

Explanation

Concept: dissolving as dispersal. Dissolving spreads solute particles through the solvent. This increases the number of microstates available.

Submit

7. Which state usually has the highest entropy (for the same substance, comparable conditions)?

Solid

Liquid

Gas

Crystal only

Concept: entropy by phase. Gases have the most molecular freedom and the largest number of accessible microstates. That generally yields the highest entropy.

Explanation

Concept: entropy by phase. Gases have the most molecular freedom and the largest number of accessible microstates. That generally yields the highest entropy.

Submit

8. Condensation (gas → liquid) usually decreases entropy of the system.

True

False

Concept: reduced freedom. Condensation reduces the number of accessible microstates as molecules become more constrained. The system entropy drops, though surroundings may increase.

Explanation

Concept: reduced freedom. Condensation reduces the number of accessible microstates as molecules become more constrained. The system entropy drops, though surroundings may increase.

Submit

9. A perfume smell spreading across a room is an example of:

Freezing

Condensation

Diffusion/mixing

Elastic collision only

Concept: mixing and probability. Perfume molecules start concentrated then spread out. The spread-out state corresponds to more microstates and higher entropy.

Explanation

Concept: mixing and probability. Perfume molecules start concentrated then spread out. The spread-out state corresponds to more microstates and higher entropy.

Submit

10. Entropy change in many thermal processes is related to heat transfer divided by ______ (qualitatively).

Concept: heat and temperature link (qualitative). Entropy connects energy transfer to temperature scale. Higher temperature generally means the same heat transfer produces a smaller entropy change.

Explanation

Concept: heat and temperature link (qualitative). Entropy connects energy transfer to temperature scale. Higher temperature generally means the same heat transfer produces a smaller entropy change.

Submit

11. During freezing, the surroundings must gain enough entropy for the total entropy change to be non-negative in a spontaneous process.

True

False

Concept: total entropy matters. Freezing can decrease the system’s entropy, but it releases heat to surroundings. If surroundings entropy rises enough, the overall process can be spontaneous.

Explanation

Concept: total entropy matters. Freezing can decrease the system’s entropy, but it releases heat to surroundings. If surroundings entropy rises enough, the overall process can be spontaneous.

Submit

12. Which process is most likely to decrease the system entropy?

Mixing two gases

Melting ice

Freezing liquid water

Expanding a gas into a larger volume

Concept: ordering and constraints. Freezing constrains molecular motion and arrangements. That reduces accessible microstates and system entropy.

Explanation

Concept: ordering and constraints. Freezing constrains molecular motion and arrangements. That reduces accessible microstates and system entropy.

Submit

13. If a gas expands into a larger volume, the entropy usually:

Decreases

Increases

Stays the same

Becomes negative

Concept: expansion increases microstates. More volume gives molecules more possible positions. That increases the number of microstates and entropy.

Explanation

Concept: expansion increases microstates. More volume gives molecules more possible positions. That increases the number of microstates and entropy.

Submit

14. Mixing is typically irreversible without doing work.

True

False

Concept: irreversibility of mixing. Mixed states are far more probable than separated ones. To unmix, you generally need external work or a separation process.

Explanation

Concept: irreversibility of mixing. Mixed states are far more probable than separated ones. To unmix, you generally need external work or a separation process.

Submit

15. When a system becomes more 'spread out' in energy and matter, its entropy generally ______.

Concept: energy/matter dispersal. Dispersal increases the number of accessible microstates. This is a practical way to predict the sign of entropy change.

Explanation

Concept: energy/matter dispersal. Dispersal increases the number of accessible microstates. This is a practical way to predict the sign of entropy change.

Submit

16. Which is a reasonable statement about boiling water?

Entropy decreases because bubbles form

Entropy increases because molecules gain freedom as a gas

Entropy is unrelated to phase changes

Entropy becomes zero at boiling

Concept: vaporisation increases entropy. Gas phase has many more configurations than liquid. Boiling therefore increases system entropy.

Explanation

Concept: vaporisation increases entropy. Gas phase has many more configurations than liquid. Boiling therefore increases system entropy.

Submit

17. Entropy can be thought of as a 'direction arrow' for many natural processes.

True

False

Concept: arrow of time. Processes tend to occur in directions that increase total entropy. This gives a statistical basis for irreversibility.

Explanation

Concept: arrow of time. Processes tend to occur in directions that increase total entropy. This gives a statistical basis for irreversibility.

Submit

18. In many everyday spontaneous processes, the total entropy change of the universe is:

Negative

Exactly zero

Positive

Undefined

Concept: real processes produce entropy. Real processes have dissipation, mixing, or finite temperature differences. These produce positive total entropy change.

Explanation

Concept: real processes produce entropy. Real processes have dissipation, mixing, or finite temperature differences. These produce positive total entropy change.

Submit

19. Which scenario best represents a decrease in system entropy but still possible overall?

Heat flowing from cold to hot without work

Water freezing while releasing heat to the surroundings

Gas spontaneously unmixing

A shattered glass reassembling

Concept: system vs surroundings. Freezing decreases system entropy but releases heat, raising surroundings entropy. The total can still be non-negative, allowing spontaneity.

Explanation

Concept: system vs surroundings. Freezing decreases system entropy but releases heat, raising surroundings entropy. The total can still be non-negative, allowing spontaneity.

Submit

20. Entropy ideas help explain why 'perfect unmixing' or 'perfectly reversing' real processes is practically impossible.

True

False

Concept: practical irreversibility. The reverse processes are overwhelmingly unlikely and require precise control and work. Entropy captures that imbalance statistically.

Explanation

Concept: practical irreversibility. The reverse processes are overwhelmingly unlikely and require precise control and work. Entropy captures that imbalance statistically.

Submit