CBSE Worksheet for Chapter - 4 Combustion And Flame Class 8

CBSE Worksheet for Chapter - 4 Combustion And Flame Class 8

Worksheets For class 8

Find CBSE Worksheet for chapter-4 Combustion And Flame class 8

CLASS-8 BOARD: CBSE Chemistry Worksheet - 4 TOPIC: Combustion And Flame For other CBSE Worksheet for class 8 Science check out main page of Physics Wallah.

SUMMARY

• Combustion- definition, combustible and non-combustible substances.
• Products of combustion, types of combustion.
• Conditions necessary for combustion.
• Flame – luminous and non-luminous.
• Different zones of candle flames.
• Fuels – types of fuels, characteristics of fuels, calorific values.
• Commonly used fuels – Hydrogen, CNG, LPG.
• Green house effect and acid rain.

SECTION – 1

1. Which zone is the hottest part of candle flame ?
   1. outer zone
   2. inner zone
   3. middle zone
   4. None of these
2. The flame produced by burning LPG is :
   1. Blue
   2. Yellow
   3. Orange
   4. Green
3. Which of the following is best fuel in terms of energy released by per unit gram of fuel ?
   1. Methane
   2. Ethane
   3. Propane
   4. Butane
4. Out of the following different types of fuels the one which is excellent is :
   1. the solid fuel
   2. the liquid fuel
   3. the gaseous fuel
   4. none of these
5. The harmful gases produced during combustion of coal and petroleum products is/are –
   1. SO₂
   2. NO₂
   3. CO
   4. All of these
6. When oxygen supply is increased in Bunsen burner, the colour of the flame changes –
   1. from blue to yellow
   2. from yellow to blue
   3. from blue to red
   4. from yellow to red
7. Which of the following is not a product of incomplete combustion ?
   1. Carbon monoxide
   2. Carbon dioxide
   3. water
   4. heat
8. Which of the following is not the attribute of a good fuel ?
   1. Low calorific value
   2. Moderate rate of combustion
   3. Fairly cheap and easily available
   4. Safe to handle, store and transport.
9. Which of the following fuels has the highest calorific value ?
   1. Petrol
   2. Hydrogen
   3. LPG
   4. Natural gas
10. Calorific value of a fuel may be defined as –
    1. The amount of heat produced when 1 Kg of fuel is completely burnt.
    2. The amount of heat produced when 1 g of fuel is completely burnt.
    3. The amount of heat produced when 10 g of fuel is completely burnt.
    4. The amount of heat produced in kilojoules when 1 g of fuel is completely burnt.

SECTION – 2

1. 11. What is an inflammable substance ?
2. 12. Write the necessary conditions for combustion ?
3. 13. A family consumes 14.5 kg of LPG in 28 days. Calculate the average energy consumed per day, if the calorific value of L.P.G. is 55 KJ/g.
4. 14. What is a flame? List the difference between luminous and non-luminous flames ?
5. 15. Write four characteristics of an ideal fuel.