Skills Worksheet Directed Reading A Section: Changes of State ENERGY AND CHANGES OF STATE Write the letter of the correct answer in the space provided. 1. What kind of change is a change of state? a. a chemical change b. a change in the identity of a substance c. a physical and chemical change d. a physical change 2. Which of the following is NOT true? a. Particles move differently depending on state. b. Energy must be added or removed to change state. c. Particles have the same amount of energy in different states. d. Particles have different amounts of energy in different states. Match the labels to the graphic. Write the letter in the space provided. b c d a 3. freezing 4. evaporation 5. condensation 6. melting Holt California Physical Science 3 States of Matter
MELTING: SOLID TO LIQUID Write the letter of the correct answer in the space provided. 7. What is a change in state from a solid to a liquid? a. freezing b. melting c. evaporation d. sublimation Melting Point 8. What is the temperature at which a solid changes to a liquid called? a. melting point b. boiling point c. freezing point d. evaporation point Adding Energy 9. What must be absorbed for a solid to melt? a. water b. atoms c. energy d. molecules FREEZING: LIQUID TO SOLID 10. What is the change in state from a liquid to a solid called? a. evaporation b. melting d. freezing Removing Energy 11. Which of the following is the same as the freezing point of an object? a. its melting point b. its evaporation point c. its sublimation point d. its boiling point Holt California Physical Science 4 States of Matter
EVAPORATION: LIQUID TO GAS 12. Which of the following is the change in state from a liquid to a gas? a. melting d. evaporation Evaporation and Boiling 13. Which of the following is the conversion of liquid to vapor throughout the liquid? a. boiling d. evaporation 14. When water is boiling, which of the following does NOT happen? a. Molecular motion increases. b. Molecular motion decreases. c. Water molecules overcome attraction. d. Water vapor escapes. Effects of Pressure on Boiling Point 15. What happens to the boiling point of a substance as you go higher above sea level? a. The boiling point gets higher. b. The boiling point stays the same. c. The boiling point gets lower. d. The substance won t boil. CONDENSATION: GAS TO LIQUID 16. What is condensation? a. the change of state from a liquid to a gas b. the change of state from a solid to a gas c. the change of state from a gas to a solid d. the change of state from a gas to a liquid 17. Which of the following must happen for gas to become a liquid? a. Small numbers of particles must clump together. b. Large numbers of particles must spread apart. c. Large numbers of particles must clump together. d. Small numbers of particles must spread apart. Holt California Physical Science 5 States of Matter
SUBLIMATION: SOLID TO GAS 18. Dry ice changes from a solid to a gas during what process? a. melting c. boiling d. sublimation 19. What happens to the particles of a substance during sublimation? a. They spread far apart. b. They clump close together. c. They lose energy. d. They maintain the same energy. TEMPERATURE AND CHANGES OF STATE 20. What happens when the temperature of a substance changes? a. The speed of the particles stays the same. b. The speed of the particles changes. c. The substance always melts. d. The substance always freezes. Holt California Physical Science 6 States of Matter
TEACHER RESOURCES Answer Key Directed Reading A SECTION: FOUR STATES OF MATTER 1. B 2. A 3. A 4. C 5. B 6. A 7. C 8. C 9. A 10. D 11. A 12. A 13. D 14. C SECTION: CHANGES OF STATE 1. D 2. C 3. A 4. C 5. D 6. B 7. B 8. A 9. C 10. D 11. A 12. D 13. A 14. B 15. C 16. D 17. C 18. D 19. A 20. B Directed Reading B SECTION: FOUR STATES OF MATTER 1. A state of matter is a physical form in which a substance can exist. 2. The three most familiar states of matter are solid, liquid, and gas. 3. atoms, molecules 4. A 5. C 6. B 7. C 8. A solid is the state of matter that has a definite shape and volume. 9. The particles in the liquid move quickly and slide past each other until the liquid takes the shape of the glass. 10. It shows that even when liquids change shape, they don t change volume. 11. A gas is a state of matter that has no definite shape or volume. 12. The tank contains helium particles that are forced close together. As helium enters the balloons, the atoms spread out, and the amount of empty space in the gas increases. 13. plasma 14. Plasmas conduct electric current, while gases do not. Electric and magnetic fields affect plasmas but do not affect gases. 15. Answers may vary. Sample answer: natural plasma: lighting; artificial plasma: fluorescent lights SECTION: CHANGES OF STATE 1. A 2. change of state 3. melting, freezing, evaporation, condensation, sublimation 4. No, gallium s melting point is lower than your body temperature. It would melt in your hand. 5. melting point 6. freezing point 7. If energy is added, melting occurs. If energy is removed, freezing occurs. 8. B 9. C 10. A 11. atmospheric pressure, boiling point 12. condensation 13. boiling point 14. clump together 15. Solid carbon dioxide is called dry ice because instead of melting, it changes from a solid directly into a gas through sublimation. Holt California Physical Science 95 States of Matter