Composition of Air
Composition of Air
1. Q: What is composed of air?
Answer:* A mixture of gases and impurities.
Answer:* A mixture of gases and impurities.
2. Q: What is the percentage of nitrogen in the atmosphere?
Answer: 78%
Answer: 78%
3. Q: What affects the amount of water vapour and impurities in the atmosphere?
Answer: Weather and location.
Answer: Weather and location.
4. Q: What is humidity?
Answer: Water vapour in the air.
Answer: Water vapour in the air.
5. Q: Where are there more impurities in the air?
Answer: Industrial areas.
Answer: Industrial areas.
6. Q: What happens to the water level in the gas cylinder when a burning candle is covered?
Answer: The water level rises to replace the air used during combustion.
Answer: The water level rises to replace the air used during combustion.
7. Q: What percentage of the gas cylinder's height does the water rise to?
Answer: About one-fifth (20%) of the height of the gas cylinder.
Answer: About one-fifth (20%) of the height of the gas cylinder.
8. Q: What does this experiment demonstrate about oxygen?
Answer: Oxygen is the gas that supports combustion, and it makes up about 20% of the air in the atmosphere.
Answer: Oxygen is the gas that supports combustion, and it makes up about 20% of the air in the atmosphere.
9. Q: What happens to the candle when it is covered with a gas jar or glass bottle?
Answer: The candle goes out due to lack of oxygen.
Answer: The candle goes out due to lack of oxygen.
10. Q: What is the purpose of using a gas jar or glass bottle in this experiment?
Answer: To create a closed environment and observe the effects of combustion on the air.
Answer: To create a closed environment and observe the effects of combustion on the air.
Activity 37: Revise Oxygen in Air
11. Q: Why did the candle stop burning?
Answer: Because the oxygen in the air was used up, and the candle did not have enough oxygen to continue burning.
Answer: Because the oxygen in the air was used up, and the candle did not have enough oxygen to continue burning.
12. Q: How much of the gas cylinder filled with water?
Answer: About one-fifth (20%) of the height of the gas cylinder.
Answer: About one-fifth (20%) of the height of the gas cylinder.
13. Q: Why was the water able to move into the gas cylinder?
Answer: Because the air in the gas cylinder was used up by the burning candle, creating a partial vacuum that allowed the water to rise.
Answer: Because the air in the gas cylinder was used up by the burning candle, creating a partial vacuum that allowed the water to rise.
14. Q: What is the gas that supports combustion?
Answer: Oxygen.
Answer: Oxygen.
15. Q: What is solubility?
Answer: How well a substance mixes with a liquid.
Answer: How well a substance mixes with a liquid.
16. Q: What are some examples of physical properties of matter?
Answer: Boiling point, appearance, density, texture, solubility, color, odor, and melting point.
Answer: Boiling point, appearance, density, texture, solubility, color, odor, and melting point.
17. Q: What are some examples of chemical properties of matter?
Answer: Reactivity with other substances, flammability, and the ability to rust or corrode.
Answer: Reactivity with other substances, flammability, and the ability to rust or corrode.
18. Q: What are some physical properties of nitrogen?
Answer: It is a colorless, odorless, and tasteless gas with a density similar to that of air.
Answer: It is a colorless, odorless, and tasteless gas with a density similar to that of air.
19. Q: What are some uses of nitrogen?
Answer: Providing a non-reactive environment, preserving historical documents, and preventing spoilage of food.
Answer: Providing a non-reactive environment, preserving historical documents, and preventing spoilage of food.
Uses of Nitrogen
20. Q: What are some uses of nitrogen?
Answer: Nitrogen is used in food packaging, preserving historical documents, and as a coolant during transportation. It is also used in the manufacture of ammonia, which is used in fertilizers.
Answer: Nitrogen is used in food packaging, preserving historical documents, and as a coolant during transportation. It is also used in the manufacture of ammonia, which is used in fertilizers.
21. Q: What is ammonia used for?
Answer: Ammonia is used in the manufacture of fertilizers, as well as in various industrial processes.
Answer: Ammonia is used in the manufacture of fertilizers, as well as in various industrial processes.
Physical Properties/Nature of Oxygen
22. Q: What are some physical properties of oxygen?
Answer: Oxygen is a colorless, odorless, and tasteless gas that is slightly soluble in water.
Answer: Oxygen is a colorless, odorless, and tasteless gas that is slightly soluble in water.
23. Q: What percentage of oxygen is present in water?
Answer: About 4% of the weight of water is oxygen.
Answer: About 4% of the weight of water is oxygen.
Uses of Oxygen
24. Q: What are some medical uses of oxygen?
Answer: Oxygen is used to increase oxygen levels in patients with conditions such as pneumonia, heart failure, and chronic obstructive pulmonary disease (COPD). It is also used in life support systems.
Answer: Oxygen is used to increase oxygen levels in patients with conditions such as pneumonia, heart failure, and chronic obstructive pulmonary disease (COPD). It is also used in life support systems.
Industrial Uses of Oxygen
25. Q: What is oxygen used for in welding and cutting metals?
Answer: Oxygen is used in Oxy-acetylene flames for welding and cutting metals.
Answer: Oxygen is used in Oxy-acetylene flames for welding and cutting metals.
26. Q: How is oxygen used in the manufacture of steel?
Answer: Oxygen is used to oxidise impurities, such as carbon, sulphur, silicon, and phosphorus, which are found in iron, resulting in pure steel.
Answer: Oxygen is used to oxidise impurities, such as carbon, sulphur, silicon, and phosphorus, which are found in iron, resulting in pure steel.
27. Q: Why is oxygen important in combustion processes?
Answer: Oxygen is necessary for combustion to occur, and it is mixed with fuel in motor car engines and rockets to cause a controlled explosion.
Answer: Oxygen is necessary for combustion to occur, and it is mixed with fuel in motor car engines and rockets to cause a controlled explosion.
28. Q: What is another industrial use of oxygen?
Answer: Oxygen is used in the purification of water and in the chemical industry for the manufacture of some chemical compounds.
Answer: Oxygen is used in the purification of water and in the chemical industry for the manufacture of some chemical compounds.
29. Q: What does the term "oxidise" mean?
Answer: To combine with oxygen or to add oxygen to a substance.
Answer: To combine with oxygen or to add oxygen to a substance.
30. Q: What is combustion?
Answer: A chemical reaction between substances, usually with oxygen, that gives off heat as a flame.
Answer: A chemical reaction between substances, usually with oxygen, that gives off heat as a flame.
Carbon Dioxide
31. Q: What are some physical properties of carbon dioxide?
Answer: Carbon dioxide is a colorless, odorless gas that is denser than air and soluble in water.
Answer: Carbon dioxide is a colorless, odorless gas that is denser than air and soluble in water.
32. Q: What are some uses of carbon dioxide?
Answer: Carbon dioxide is used in fire extinguishers, carbonated drinks, refrigeration, bakeries, and by green plants during photosynthesis.
Answer: Carbon dioxide is used in fire extinguishers, carbonated drinks, refrigeration, bakeries, and by green plants during photosynthesis.
33. Q: Why is carbon dioxide useful in fire extinguishers?
Answer: Because it is non-flammable, denser than air, and does not support combustion.
Answer: Because it is non-flammable, denser than air, and does not support combustion.
34. Q: What is dry ice, and how is it made?
Answer: Dry ice is a white solid made from liquid carbon dioxide that has evaporated. As the solid carbon dioxide forms, the temperature falls to -78 °C.
Answer: Dry ice is a white solid made from liquid carbon dioxide that has evaporated. As the solid carbon dioxide forms, the temperature falls to -78 °C.
35. Q: What happens when dry ice is heated?
Answer: It sublimates, leaving no residue and cooling the surroundings.
Answer: It sublimates, leaving no residue and cooling the surroundings.
Hydrogen
36. Q: What are some physical properties of hydrogen?
Answer: Hydrogen is a colorless, odorless gas that is less dense than air.
Answer: Hydrogen is a colorless, odorless gas that is less dense than air.
37. Q: What are some uses of hydrogen?
Answer: Hydrogen is used in the production of ammonia, refining petrol, extracting metals, producing fertilizers, and hardening vegetable oils.
Answer: Hydrogen is used in the production of ammonia, refining petrol, extracting metals, producing fertilizers, and hardening vegetable oils.
Activity 38: Recall What You Know About Gases
38. Q: List three medical uses of oxygen.
Answer: Oxygen is used in ventilators, treating patients with chronic obstructive pulmonary disease (COPD), and patients on life support systems.
Answer: Oxygen is used in ventilators, treating patients with chronic obstructive pulmonary disease (COPD), and patients on life support systems.
39. Q: List four industrial uses of oxygen.
Answer: Oxygen is used in welding and cutting metals, manufacturing steel, in rocket fuel, and in the purification of water.
Answer: Oxygen is used in welding and cutting metals, manufacturing steel, in rocket fuel, and in the purification of water.
40. Q: List five uses of carbon dioxide.
Answer: Carbon dioxide is used in fire extinguishers, carbonated drinks, refrigeration, bakeries, and by green plants during photosynthesis.
Answer: Carbon dioxide is used in fire extinguishers, carbonated drinks, refrigeration, bakeries, and by green plants during photosynthesis.
41. Q: List five uses of hydrogen.
Answer: Hydrogen is used in the production of ammonia, refining petrol, extracting metals, producing fertilizers, and hardening vegetable oils.
ConclusionIn conclusion, we have explored the composition of air, including the physical properties and uses of oxygen, nitrogen, carbon dioxide, and hydrogen. We have learned about the importance of oxygen in supporting combustion and its various industrial and medical applications. We have also discussed the uses of nitrogen, carbon dioxide, and hydrogen in various industries, including manufacturing, refining, and agriculture.Final RemarksUnderstanding the properties and uses of the gases in the air is crucial for various industrial, medical, and environmental applications. It is essential to recognize the importance of these gases in our daily lives and to use them responsibly to ensure a sustainable future.Key Takeaways- Oxygen is essential for combustion and has various industrial and medical applications.
- Nitrogen is used in food packaging, preserving historical documents, and as a coolant.
- Carbon dioxide is used in fire extinguishers, carbonated drinks, refrigeration, bakeries, and by green plants during photosynthesis.
- Hydrogen is used in the production of ammonia, refining petrol, extracting metals, producing fertilizers, and hardening vegetable oils.
I hope this summary is helpful! Let me know if you have any further questions.
Answer: Hydrogen is used in the production of ammonia, refining petrol, extracting metals, producing fertilizers, and hardening vegetable oils.
Conclusion
In conclusion, we have explored the composition of air, including the physical properties and uses of oxygen, nitrogen, carbon dioxide, and hydrogen. We have learned about the importance of oxygen in supporting combustion and its various industrial and medical applications. We have also discussed the uses of nitrogen, carbon dioxide, and hydrogen in various industries, including manufacturing, refining, and agriculture.
Final Remarks
Understanding the properties and uses of the gases in the air is crucial for various industrial, medical, and environmental applications. It is essential to recognize the importance of these gases in our daily lives and to use them responsibly to ensure a sustainable future.
Key Takeaways
- Oxygen is essential for combustion and has various industrial and medical applications.
- Nitrogen is used in food packaging, preserving historical documents, and as a coolant.
- Carbon dioxide is used in fire extinguishers, carbonated drinks, refrigeration, bakeries, and by green plants during photosynthesis.
- Hydrogen is used in the production of ammonia, refining petrol, extracting metals, producing fertilizers, and hardening vegetable oils.
I hope this summary is helpful! Let me know if you have any further questions.
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