Physical Science Chapter 3 Homework Answers Section Review SECTION: THREE STATES OF MATTER (PAGE 69) 1. A liquid with a high viscosity does not flow very easily. Water can form spherical droplets because of its surface tension. 2. C 3. The shape and volume of a solid does not change. Liquids take the shape of their container, but their volume does not change. Gases completely fill their container and can vary in volume. 4. Apple juice is a liquid, bread is a solid, a textbook is a solid, and steam is a gas. 5. The particles of a gas are very far apart with empty space between them. If the gas is compressed, the particles are pushed closer together, so the volume of the gas decreases. The particles of a solid are very close together and are strongly attracted to each other. Each particle is locked in place by the particles around it, so the shape of the solid does not change. 6. The matter shown in the jar represents a solid. 7. The particles have a strong attractive force between them that keeps them from moving apart from each other.
SECTION: BEHAVIOR OF GASES (PAGE 73) 1. Charles’s law states that when the temperature of a gas under constant pressure is decreased, the volume of the gas decreases. 2. A 3. When gas particles become warmer, they move more rapidly and hit the sides of their container more often and with greater force, thus increasing the volume of the gas. 4. The volume of the gas would also double to 6 L. 5. The volume of the balloon will decrease. When the air particles inside the balloon become cooler, they slow down and do not hit the inside of the balloon as often, so the balloon’s volume decreases. 6. The volume, pressure and temperature of a gas are all related. The volume of a gas can be changed by changing the temperature and the pressure. 7. Boyle’s law states that the volume of a gas is inversely proportional to its pressure. If the volume is tripled, the pressure of the gas would drop to one-third of the original value.
SECTION: CHANGES OF STATE (PAGE 79) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Melting changes a solid to a liquid. Freezing changes a liquid to a solid. Condensation changes a gas to a liquid. Evaporation changes a liquid to a gas. D As a substance freezes, its particles lose some of their freedom of motion and become more orderly. The temperature of the ice cube stays constant until the change of state is complete. Evaporation occurs only at the surface of a liquid and boiling occurs throughout a liquid. Both evaporation and boiling are endothermic processes that change a liquid to a gas. 18,000 mL This reaction is exothermic. The temperature increased because energy was released during the reaction. sublimation; The solid crystals were heated and turned directly into vapor. no; Dry ice is solid carbon dioxide. It undergoes sublimation and turns into a vapor.
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Physical Science Chapter 3 Homework Answers
Chapter Review (Pages 82-83) 1. Solid is the state of matter in which the substance has a definite shape and volume. Liquid is the state in which the substance takes the shape of its container but has a definite volume. 2. Boyle’s law states that when the pressure of a gas increases at a constant temperature, its volume decreases. Charles’s law states that when the temperature of a gas increases at a constant pressure, its volume increases. 3. Evaporation is the change of a liquid to a gas at the surface of a liquid. Boiling is the change of a liquid to a gas throughout a liquid. 4. Condensation is the change of a gas to a liquid. Sublimation is the change of a substance from a solid to a gas without becoming a liquid. 5. B 6. B 7. B 8. A 9. B 10. C 11. A 12. D 13. The particles of liquid water can move past one another and take the shape of a container. Particles in an ice cube are locked in place and cannot move past one another. An ice cube holds its shape no matter what container you put it in. 14. gases, liquids, solids 15.
The graph is linear. Both variables (surface area and volume evaporated) increase together. 17. The splitting of water into hydrogen and oxygen is not a change of state because the substance (water) does not keep its identity during the change. The water is changed into two new substances, hydrogen and oxygen. 18. As you take a shower, some of the liquid water evaporates and becomes a gas. When the gaseous water touches the mirror, the water releases energy to the mirror and condenses into drops of liquid water. 19. Freezing is an exothermic change. As the water freezes, it releases energy. The oranges absorb some of this energy and warm up. (The ice also helps to insulate the oranges from the cold air.) 20. Water has a stronger force of attraction between its particles; A higher temperature, and therefore more energy, is required to separate the water particles from one another than is needed to separate the methane particles from one another. 21. 80ºC; 20ºC 22. liquid 23. The temperature of the liquid will rise.
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