Plasmas (p. 67) 24. More than 99 percent of the known matter in the universe is in the plasma state. 25. Plasmas are made up of particles that have broken apart. 26. Plasmas have a definite shape and volume. 27. Plasmas and gases conduct electric current. 28. Plasmas are affected by magnetic fields. 29. Lightning and fire are examples of plasmas. 30. The incredible light show in Figure 12, on page 67, is caused by plasma. How? Review (p. 67) Now that you ve finished Section 1, review what you learned by Section 2: Changes of State (p. 68) 1. When a substance changes from one form to another, we say the substance has had a change of state. 2. List the five changes of state. Energy and Changes of State (p. 68) 3. The identity of a substance changes during a change of state. 4. Temperature is the measure of the speed of particles. 5. Temperature is a transfer of energy. 6. Which has the most energy? a. particles in steam c. particles in ice b. particles in liquid water d. particles in freezing water 20 HOLT SCIENCE AND TECHNOLOGY
Melting: Solids to Liquids (p. 69) 7. Could you use gallium to make jewelry? Why or why not? 8. Melting point is a characteristic property, because it is the same for different amounts of the same substance. True or False? (Circle one.) Freezing: Liquids to Solids (p. 69) 9. A substance s freezing point is the temperature at which it changes from a to a. 10. What happens if energy is added or removed from the ice water in Figure 15? 11. Freezing is considered an exothermic change because is removed from the substance. Vaporization: Liquids to Gases (p. 70) Choose the term in Column B that best matches the description in Column A, and write the corresponding letter in the space provided. Column A 12. vaporization at the surface of a liquid below its boiling point 13. the change of state from a liquid to a gas 14. vaporization that occurs throughout a liquid 15. the product of vaporization of liquid water 16. temperature at which a liquid boils Column B a. boiling point b. vaporization c. steam d. evaporation e. boiling CHAPTER 3 DIRECTED READING WORKSHEETS 21
Condensation: Gases to Liquids (p. 71) 17. At a given pressure, the condensation point for a substance is the same as its melting point. 18. For a substance to change from a gas to a liquid, particles must clump together. 19. Condensation is an exothermic change. Sublimation: Solids Directly to Gases (p. 72) 20. Solid carbon dioxide isn t ice. So why is it called dry ice? 21. The change of state from a solid to a is called sublimation. Energy must be added for sublimation to occur, so it is an change. Comparing Changes of State (p. 72) 22. Look at the table on page 72. Which two changes of state occur at the same temperature? a. condensation and melting b. sublimation and freezing c. vaporization and condensation d. melting and vaporization Temperature Change Versus Change of State (p. 73) Figure 19 may help you. 23. The speed of the particles in a substance changes when the temperature changes. 24. The temperature of a substance changes before the change of state is complete. 25. Energy must be added to a substance to move its temperature from the melting point to the boiling point. Review (p. 73) Now that you ve finished Section 2, review what you learned by 22 HOLT SCIENCE AND TECHNOLOGY
Plasmas (p. 67) 24. True More than 99 percent of the known matter in the universe is in the plasma state. 25. True Plasmas are made up of particles that have broken apart. 26. False Plasmas have a definite shape and volume. 27. False Plasmas and gases conduct electric current. 28. True Plasmas are affected by magnetic fields. 29. Lightning and fire are examples of natural plasmas. 30. The incredible light show in Figure 12, on page 67, is caused by plasma. How? High-energy plasma collides with particles in the upper atmosphere, causing them to glow. Review (p. 67) Now that you ve finished Section 1, review what you learned by Section 2: Changes of State (p. 68) 1. When a substance changes from one physical form to another, we say the substance has had a change of state. 2. List the five changes of state. melting, freezing, vaporization, condensation, and sublimation Energy and Changes of State (p. 68) 3. The identity of a substance changes during a change of state. 4. Temperature is the measure of the speed of particles. 5. Temperature is a transfer of energy. 6. Which has the most energy? a. particles in steam c. particles in ice b. particles in liquid water d. particles in freezing water 20 HOLT SCIENCE AND TECHNOLOGY
Melting: Solids to Liquids (p. 69) 7. Could you use gallium to make jewelry? Why or why not? No; gallium s melting point is lower than your body temperature. It would melt in your hand. 8. Melting point is a characteristic property, because it is the same for different amounts of the same substance. True or False? (Circle one.) Freezing: Liquids to Solids (p. 69) 9. A substance s freezing point is the temperature at which it changes from a liquid to a solid. 10. What happens if energy is added or removed from the ice water in Figure 15? If energy is added, melting occurs. If energy is removed, freezing occurs. 11. Freezing is considered an exothermic change because energy is removed from the substance. Vaporization: Liquids to Gases (p. 70) Choose the term in Column B that best matches the description in Column A, and write the corresponding letter in the space provided. d b e c a Column A 12. vaporization at the surface of a liquid below its boiling point 13. the change of state from a liquid to a gas 14. vaporization that occurs throughout a liquid 15. the product of vaporization of liquid water 16. temperature at which a liquid boils Column B a. boiling point b. vaporization c. steam d. evaporation e. boiling CHAPTER 3 DIRECTED READING WORKSHEETS 21
Condensation: Gases to Liquids (p. 71) 17. False At a given pressure, the condensation point for a substance is the same as its melting point. 18. True For a substance to change from a gas to a liquid, particles must clump together. 19. True Condensation is an exothermic change. Sublimation: Solids Directly to Gases (p. 72) 20. Solid carbon dioxide isn t ice. So why is it called dry ice? It s called dry ice because it doesn t melt. It changes from a solid directly into a gas through sublimation. 21. The change of state from a solid to a gas is called sublimation. Energy must be added for sublimation to occur, so it is an endothermic change. Comparing Changes of State (p. 72) 22. Look at the table on page 72. Which two changes of state occur at the same temperature? a. condensation and melting b. sublimation and freezing c. vaporization and condensation d. melting and vaporization Temperature Change Versus Change of State (p. 73) Figure 19 may help you. 23. True The speed of the particles in a substance changes when the temperature changes. 24. False The temperature of a substance changes before the change of state is complete. 25. True Energy must be added to a substance to move its temperature from the melting point to the boiling point. Review (p. 73) Now that you ve finished Section 2, review what you learned by 22 HOLT SCIENCE AND TECHNOLOGY