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German problems 2015
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tutor 7.pptx

  1. 1. Q & A CHAPTER 7: AIR
  2. 2. 1. The pie chart in Figure 1 shows the percentage of gas P, Q, R and S in the atmosphere (a) Determine gas (i) P (ii) Q (iii) R (iv) S P: Nitrogen Q: Oxygen R: Inert gases S: Carbon dioxide
  3. 3. (b) State the importance of gas P. (c) What would happen to the temperature of Earth if the percentage of gas S increases? Give a reason for your answer. (d) Give one reason why air is considered a mixture. • Needed to produce nitric acid and ammonia • Helps in animal and plant growth The temperature increases because gas S traps heat Air components can be separated physically.
  4. 4. 2. Solve the crossword puzzle below with the correct answer. Horizontal: (a)Carbon cycle maintains this gas in the air. (b) This gas is used to fill up light bulbs. Vertical: (c) A layer that surrounds the Earth. (d) This gas is needed in combustion.
  5. 5. 3. Figure 2 shows the percentage of carbon dioxide in a period of time.
  6. 6. (a) Logging activities increase the amount of carbon dioxide in the atmosphere. How does it contribute to the increase of carbon dioxide level in the atmosphere? Explain. Green plants are the only living things that can absorb and reduce carbon dioxide in the atmosphere through photosynthesis. When a lot of trees are cut down, carbon dioxide which is released through respiration, combustion and decomposition will increase the percentage of carbon dioxide in the atmosphere.
  7. 7. (c) State two effects if the rate of carbon dioxide in the atmosphere increases continuously (b) Other than logging, give one activity that contributes to the increase of carbon dioxide in the atmosphere. Burning of fossil fuel / burning of forests Greenhouse effect and global warming
  8. 8. 4. Ammar witnessed a fire at a workshop on his way home from school. The fire was caused by a short circuit. (a) What is combustion? (b) State the conditions of combustion. Combustion is the reaction where a substance reacts with oxygen chemically and produces heat and light energy Heat, oxygen and fuel.
  9. 9. (c) Based on the situation, (i) how does one prevent such a fire from happening? (ii) what fire extinguisher is suitable? Ensure electrical wirings are according to the right specifications Use dry powder fire extinguisher.
  10. 10. (d) State three precautions that should be practised to prevent fire from happening • Install smoke detectors and fire alarm at home • Do not plug in too many appliances on a single electrical source • Always be aware of the electrical appliances used
  11. 11. 5. Figure 3 shows a situation that occurs in Kuala Lumpur. (a) What is the environmental problem shown in Figure 3? Haze
  12. 12. (b) State two effects of the problem you mentioned in 5(a) towards health. (c) The road accident rate increases when this environmental problem occurs. Why? Causes breathing difficulties and cough The visibility distance is limited
  13. 13. 6. The oxygen level in a cave would eventually decrease as we walk further into the cave.
  14. 14. (a)List a few reasons why the oxygen level decreases in the cave. (b)If we want to go into a deep cave, we are encouraged to bring torches with us in addition to torchlights as an indicator to show the presence of oxygen. How does the torch function? Explain. This is caused by natural processes such as the decay of organisms like dead bats in the cave and the respiration of bats or other animals inside the cave. This process reduces the level of oxygen in the cave The flame of the torch will extinguish when the oxygen level is too low. Thus, the use of the torch can warn us not to continue the exploration when we reach the area with low oxygen level.
  15. 15. (c) Do you think it is good to bring torches into the cave? (d) Suggest one way to detect the oxygen level in a safer way. Give one reason for your suggestion. No, because we do not know the exact amount of oxygen in the cave. In addition, the torch will increase the level of carbon dioxide in the cave. Use an oxygen sensor to know the exact level of oxygen and take precautions.

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