Phase Change Test Study Guide



Phase Change Test Study Guide

Vocabulary Definitions (Use Your Notebook): 

  1. Freedom of movement- the way molecules in a substance move around relative to each other

  2. Kinetic energy -the energy that an object has because it is moving

  3. Molecular Attraction-=a pull between two molecules that is always the same for a substance

  4. Molecule -a group of atoms joined together in a particular way

  5. Phase -a noticeably different form or state of the same substance

  6. Scale-the relative size of things

  7. Temperature-a measure of how hot or cold something is

Fill in the blank 

  1. When you transfer energy into a substance the molecules’ kinetic energy increases___________. 

  2. When you transfer energy into a substance, the temperature ___increases____________________. 

  3. When the kinetic energy of molecules decreases, the molecules are moving slower_______________. 

  4. When a substance changes from one physical form to another, we say the substance has had a(n) _____phase change_______________. 

Questions: 

  1. Look at the description of the molecular scale and determine the phase (solid, liquid, or gas).

Description (molecular scale)

Liquid, Gas, or Solid

  1. Can move in place: 

Solid

  1. Can move around each other: 

Liquid

  1. Can move apart: 

Gas



  1. Label the phase change in this diagram 

Evaporation

Condensation

Freezing

Melting

  1. Freezing

  1. Melting

  1. Condensation

D.   Evaporation



Use the vocabulary words from above to answer the questions in complete sentences



14. What happens to the molecules of a substance when it changes phase? 

  • The freedom of movement changes.



15. How can we tell how fast the molecules move if we can’t see them? 

  • The temperature can help us because when there hot they move a lot 



16. Why does an energy transfer not always result in a phase change? 

  • When there's too much or too little molecular attraction. 



17. What happens if energy is added from a glass of ice water? 

  • The phase of the ice water would change into gas.

18. What happens if energy is removed from a glass of ice water? 

  • The phase would change into a solid.

19. Which of the following has the more kinetic energy? (Highlight your answer)

  1. Particles of steam.    B. Particles in liquid water.    C. Particles in ice.    D. Particles in freezing water. 



20. Which order of phases has the particles moving from FASTEST to SLOWEST?  (Highlight your answer)

  1. liquid-solid-gas   B. solid-liquid-gas   C. solid-gas-liquid   D. gas-liquid-solid



21. You have two liquids at room temperature. You transfer the same amount of energy out of both liquids but only one substance changes phase. What happened? (Highlight your answer)

  1. The substance with the weaker attraction will change to a gas

  2. The substance with the stronger attraction will turn to a gas

  3. The substance with the stronger attraction will turn to a solid

  4. The substance with the weaker attraction will turn to a solid 



22. Compare each model, what model shows a phase change occurring? Explain how you know.  

Explain: 

The model that shows phase change is Model A because it shows  it being liquid rather than turning into gas.



23. Describe what this diagram shows about molecular attraction. 



Different liquids have different molecular attractions.