Air Book Back Questions 8th Science Lesson 11
8th Science Lesson 11
11] Air
Book Back Questions with Answer and Do You Know Box Content
Do You Know?
If oxygen has the capacity to burn itself, striking a match stick will be enough to burn all the oxygen in our planet’s atmosphere.
Oxygen is about two times more soluble in water than nitrogen. If it had the same solubility as nitrogen, then less oxygen would be present in seas, lakes and rivers that will make life much more difficult for living organisms.
Now-a-days nitrogen is used as a substitute for compressed air in tyres. Have you noticed it? Why do people prefer nitrogen instead of compressed air in tyres?
The process of conversion of solid into vapour without reaching liquid state is called sublimination.
Venus’ atmosphere consists of roughly 96-97% carbon dioxide. Because of the amount of carbon dioxide present, the surface of Venus continually retains heat and as such, the surface temperature of Venus is roughly 462oC, making it the hottest planet in our solar system.
Aerated water is nothing but carbon dioxide dissolved in water under pressure. This is also called ‘soda water’.
Acid rain has pH less than 5.6 whereas pH of pure rain water is around 5.6 due to dissolution of atmospheric CO2 in it.
Choose the best answers:
1. Which of the following is true about oxygen?
(a) Completely burning gas
(b) Partially burning gas
(c) Doesn’t support burning
(d) Supports burning
2. Aerated water contains
(a) Air
(b) Oxygen
(c) Carbon dioxide
(d) Nitrogen
3. Solvay process is a method to manufacture
(a) Lime water
(b) aerated water
(c) distilled water
(d) sodium carbonate
4. Carbon dioxide with water changes
(a) Blue litmus to res
(b) red litmus to blue
(c) Blue litmus to yellow
(d) doesn’t react with litmus
5. Which of the following is known as azote?
(a) Oxygen
(b) nitrogen
(c) Sulphur
(d) Carbon dioxide
Fill in the blanks:
1. ____________ is called as vital life.
2. Nitrogen is ____________ than air.
3. ____________ is used as a fertilizer.
4. Dry ice is used as a ______________.
5. The process of conversion of iron into hydrated form of oxides is called _______________.
Match the following:
1. Nitrogen – respiration in living animals
2. Oxygen – fertilizer
3. Carbon dioxide – refrigerator
4. Dry ice – fire extinguisher
Answers:
Choose the best answers:
1. Supports burning 2. Carbon dioxide 3. Sodium Carbonate 4. blue litmus to red 5. Nitrogen
Fill in the blanks:
1. Oxygen 2. Lighter 3. Nitrogen 4. Refrigerant 5. Rusting
Match the following:
1. Nitrogen- Fertilizer
2.Oxygen- Respiration in living animals
3.Carbon dioxide- Fire extinguisher
4.Dy ice- Refrigerator