Chemistry ICSE Class 6 Important Questions Chapter 6 Air
Practice Questions
Question 1.
Who showed that oxygen is needed for respiration and burning of substances and that ratio of active and inactive component in air (oxygen and nitrogen) is 1 : 4
Answer:
Antoine Lavoisier
Question 2.
Who discovered oxygen ?
Answer:
Carl Wilhelm Scheele
Question 3.
What is the importance of water vapour in air ?
Answer:
- It provides water for plants and animals as water vapour gets converted into rain and snow.
- Controls evaporation – Excess water vapour in the atmosphere decreases the rate of evaporation.
- Determines climatic conditions – Excess water vapour in the atmosphere produces rain, mist, snow, etc.
Question 4.
What is green house effect and global warming ? Name few greenhouse gases.
Answer:
The greenhouse effect is a natural porcess in which certain gases known as greenhouse gases trap heat that radiates from the earth’s surface and re-radiate some of it back towards the earth. This results in warming the earth’s environment. The phenomenon of increasing air temperature near the surface of the earth is known as global warming. Carbon dioxide, water vapour, methane and nitrous oxide are some greenhouse gases.
Question 5.
List few uses of inert gases.
Answer:
- Helium is used in weather balloons.
- Neon is used in advertisement signs and brake lights.
- Argon is used to fill electric bulbs.
- Krypton and xenon are used in photography and in powerful lamps, such as lighthouse, etc.
Question 6.
Name the types of combustion with one example of each.
Answer:
Types of combustion – Example
1. Rapid or fast combustion – Burning of fuels
2. Slow combustion – Respiration, rusting
3. Spontaneous combustion – Oil rigs bursting into flame
Question 7.
Show the balance of oxygen and carbon dioxide in the atmosphere.
Answer:
Processes that consume carbon dioxide from the air :
Photosynthesis by green plants
Absorption of carbon dioxide by water in large waterbodies like oceans, rivers
Processes that consume oxygen from the air :
1. Respiration by plants and animals
2. Binning of fuels
Processes that release carbon dioxide into the air :
- Respiration of living organisms
- Burning of fuels such as coal and wood
- Decay of dead plants and animals
- Eruption of volcanoes.
Process that releases oxygen into the air :
Photosynthesis is the only natural process that gives out oxygen.
Question 8.
How do paints and grease or oil prevent rusting of iron?
Answer:
Paint, grease and oil when applied on iron surface, prevent air and moisture from coming in contact with iron and hence no rusting takes place.
Question 9.
Name one alloy made to prevent rusting of iron.
Answer:
Stainless steel is an alloy of iron made by mixing iron with corrosion – resistant metals like nickel and chromium.
Question 10.
Name few methods to prevent rusting of iron.
Answer:
Painting, applying grease or oil, galvanization, electroplating and alloy formation.
Question 11.
Fill in the blanks.
1. About 90% of the atmosphere lies within a height of ………….. from the earths surface.
Answer:
About 90% of the atmosphere lies within a height of 15 km from the earths surface.
2. The atmosphere acts as a screen and blocks out the harmful …………. radiation from the sun.
Ans. The atmosphere acts as a screen and blocks out the harmful ultraviolet radiation from the sun.
3. …………. acts as a medium through which sound travels.
Answer:
Air acts as a medium through which sound travels.
4. …………. is colourless, odourless and tasteless mixture of gases.
Answer:
Air is colourless, odourless and tasteless mixture of gases.
5. Water vapours condense on …………. particles in the atmopshere and cause rain.
Answer:
Water vapours condense on dust particles in the atmopshere and cause rain.
6. The air we breathe in is called …………… air and is rich in oxygen, whereas the air we breathe out is called …………… air and is rich in carbon dioxide.
Answer:
The air we breathe in is called inhaled air and is rich in oxygen, whereas the air we breathe out is called exhaled air and is rich in carbon dioxide.
7. Respiration is also a type of …………..
Answer:
Respiration is also a type of burning.
8. ………….. part of air helps in burning.
Answer:
One-fifth part of air helps in burning.
9. Red phosphorous undergoes ……………. combustion and should be handled with care.
Answer:
Red phosphorous undergoes spontaneous combustion and should be handled with care.
ICSE Class 6 Chemistry Important Questions