INTERACTIVE SCIENCE 1B

Transcription

1 INTERACTIVE SCIENCE 1B Workbook Solutions (Enrichment Edition) Chapter 6 MATTER as PARTICLES Part A Sectional Exercise 6.1 Fill in the blanks p (a) liquid (b) gas 2. (a) Melting (b) unchanged 3. boiling 4. freezing 5. (a) fixed (b) volume Questions p.54 (a) Boiling (b) Condensation (c) Melting (d) Condensing (e) Freezing (f) Melting 6.2 Concept checking p False 4. False 6. True 7. True 8. True 6.1

2 Questions p.56 (a) Air particles (Or other reasonable answers) (b) Brownian motion (c) They are constantly moving. There are spaces between them. (d) 6.3 Fill in the blanks p.57 (a) closely (b) regular (c) vibrate (d) solid (e) irregularly (f) move (g) liquid (h) far (i) any (j) gas Concept checking p True 2. False 4. True 6. False 6.4 Multiple choice p

3 1. B 2. C 3. A 4. D 5. A Concept checking p True 3. True 4. False Fill in the blanks p Bourdon gauge/pressure gauge 2. pascal 3. increases 4. collapses 5. constantly Questions p (a) The balloon inflates. (b) decreases less greater inflates 6.5 Concept checking p False 4. True 5. True 6. True Questions p (a) 16,

4 3, , 5 2, , 245 (b) The overall density of the piece of wood and the plastic box = ( ) g / 45 cm 3 = 0.84 g/cm 3. Since the overall density of the piece of wood and the plastic box is less than that of water, they will float. Therefore, Mabel will fail. 6.6 Concept checking p,62 1. True 4. False 5. True 6. True Questions p (a) expands (b) fewer (c) decreases (d) lower 2. (a) (c) (d) Part B Integrated Exercise Concept checking p False 4. True 6. False 7. False 8. True 9. False 6.4

5 10. True 11. False 12. False Multiple choice p D 2. C 3. B 4. B 5. B 6. B 7. C 8. A 9. C 10. C 11. D 12. B 13. D 14. B Questions p (a) Atoms (b) gas (c) Brownian (d) contract (e) liquids (f) melts (g) spaces between (h) solid 2. (a) straw<liquid X<wooden block< water<stone (b) Iron, copper, gold, silver, etc. (Any three reasonable answers) (c) Oil (or other reasonable answer) (d) A fish has a swim bladder which can be inflated with air or deflated. When the swim bladder is inflated, the fish is less dense than the water, so it floats; when the swim bladder is deflated, the fish is denser than the water, so it sinks. 3. (a) The vibrator is used to set the small beads into motion. (b) The beads represent particles. (c) It demonstrates the gas state because the beads can move about in any directions 6.5

6 and they are far apart from each other. (d) No. When the vibrator is turned off, the beads will stop moving. However, the particles of a substance in the solid state still vibrate within a fixed position. 4. (a) 10 g (b) 5 cm 3 (c) 10 g 5 cm 3 = 2 g/cm 3 (d) (i) The density of the piece of wood is lower than that of water. The piece of wood will float in water and hence he cannot use the same method to find its volume. (ii) He can weigh the piece of wood. Then, he can tie it to a stone and measure the total volume of them. The volume of the piece of wood can be found by subtracting the volume of the stone from the total volume. Finally, calculate the density of the piece of wood by using the formula: mass volume. 5. (a) Since the glass wall was thick, heat energy could not pass from the inner part to the outer part of the wall very quickly. The inner part was much hotter and expanded more than the outer part. The uneven expansion of the wall made it crack. (b) Yes. Using a glass with a thin wall, the heat energy can pass from the inner part to the outer part of the wall very quickly. Therefore, no uneven expansion will occur. (c) Metal cup (Or other reasonable answers) Part C Concept Diagram p gas 2. liquid 3. solid 4. condenses 5. freezes 6. melts 7. evaporates/boils 8. Bourdon gauge 9. a 10. no 11. a 12. a 13. no 14. particle/atom 15. density 16. mass per unit volume 6.6

7 17. expansion and contraction Part D Reading Comprehension p.73 (a) (i) When heated, the gas particles have more energy. They move fastrer and the spaces between them become larger. Hence, the gas expands. (ii) From (i), for the same mass of warm air and cool air, the volume of warm air is greater. So, density of warm air is lower than that of cool air and warm air rises. (b) 60 kg 600/200 = 180 kg (c) The volume and temperature of air inside the balloon. Part E Little Einstein s Corner p (a) It is nonflammable. It is denser than air/oxygen. (Or any two reasonable answers) (b) The pressurised carbon dioxide inside the fire extinguisher has a gas pressure higher than the air pressure outside. So the carbon dioxide inside can be expelled from the extinguisher./it is to store a larger amount of carbon dioxide inside the fire extinguisher. (Or other reasonable answers) (c) (i) The carbon dioxide changes from liquid state to gas state when it is expelled. This change requires energy which it absorbs from the surrounding air. Consequently the surrounding air is cooled down. (ii) The cooling effect of the carbon dioxide makes the surrounding water vapour condense rapidly into water and then freeze into ice. 2. (a) Yes, it is in liquid state because it has a fixed volume but no fixed shape. (b) Yes, it is in solid state because it has a fixed volume and a fixed shape. (c) No (d) Chemical change (e) Peter is wrong. The changes of states (melting, boiling, freezing, etc.) are all physical changes. However, the case mentioned by Peter is a chemical change. 6.7