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Quiz Chapter 7: Air

10 questions ยท Form 1 Science Bab 7: Air

Question 1 of 10Score: 0

Which percentage accurately represents the proportion of Oxygen gas in clean dry air?

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. Which percentage accurately represents the proportion of Oxygen gas in clean dry air?

  1. 78%
  2. 21%
  3. 1%
  4. 0.03%
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Answer: B

Oxygen makes up approximately 21% of clean atmospheric air.

2. Which practice directly reduces atmospheric air pollution caused by vehicle emissions?

  1. Open burning of garden waste
  2. Using public transportation or carpooling
  3. Increasing fossil fuel consumption in power stations
  4. Deforestation for agricultural land
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Answer: B

Utilizing public transportation or carpooling lowers the number of individual motor vehicles on roads, reducing exhaust emissions.

3. Which three elements make up the Fire Triangle required for combustion?

  1. Fuel, Nitrogen, Heat
  2. Fuel, Oxygen, Heat
  3. Carbon dioxide, Oxygen, Fuel
  4. Spark, Fuel, Nitrogen
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Answer: B

Combustion requires three elements simultaneously: Fuel, Oxygen, and Heat.

4. Which gas present in air is essential for green plants to undergo photosynthesis?

  1. Oxygen
  2. Nitrogen
  3. Carbon dioxide
  4. Argon
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Answer: C

Green plants absorb carbon dioxide from the air to synthesize glucose during photosynthesis.

5. Why does covering a burning pan with a damp towel extinguish the fire?

  1. It removes the fuel source
  2. It cuts off oxygen supply and lowers heat
  3. It introduces carbon monoxide to stop burning
  4. It increases air circulation
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Answer: B

The wet towel creates a barrier that blocks oxygen gas from reaching the flame and absorbs heat energy.

6. Which process removes carbon dioxide from atmospheric air?

  1. Combustion of fossil fuels
  2. Decay of organic material
  3. Photosynthesis
  4. Volcanic eruption
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Answer: C

Photosynthesis is the sole natural process that absorbs carbon dioxide directly from the atmosphere.

7. Which gas glows with a bright orange-red light when electric current passes through it in neon signage?

  1. Helium
  2. Neon
  3. Argon
  4. Nitrogen
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Answer: B

Neon gas emits a distinct reddish-orange glow when electrified in discharge tubes used for advertising signs.

8. How does spraying cold water onto a wood fire put it out?

  1. It converts wood fuel into carbon dioxide
  2. It cools the fuel below its ignition temperature
  3. It generates oxygen gas to overwhelm the fire
  4. It reacts chemically to dissolve the charcoal
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Answer: B

Water absorbs significant heat energy as it turns to steam, lowering the temperature of the burning wood below its ignition threshold.

9. Which biological activity consumes oxygen gas from the air?

  1. Photosynthesis
  2. Respiration
  3. Transpiration
  4. Nitrogen fixation
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Answer: B

Cellular respiration in living organisms consumes oxygen to break down glucose and release energy.

10. Which two gases dissolve in rainwater to form acid rain?

  1. Oxygen and Carbon monoxide
  2. Sulfur dioxide and Nitrogen dioxide
  3. Carbon dioxide and Helium
  4. Methane and Ozone
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Answer: B

Sulfur dioxide and nitrogen dioxide dissolve in atmospheric moisture to form sulfuric acid and nitric acid, producing acid rain.

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