CBSE Class 8 Science Combustion and Flame Assignment

Question. Element showing spontaneous combustion is
(a) Calcium
(b) Phosphorous
(c) Lithium
(d) Copper

Answer : C

Question. Which of the following is/are carbon fuel
(a) Wood
(b) Coal
(c) Petroleum
(d) All of these

Answer : D

Question. Combustion of most fuels releases
(a) CO2
(b) SO2
(c) NO2
(d) Oxygen

Answer : A 

Question. Acid rain is caused by oxides of
(a) Sulphur, Nitrogen
(b) Sulphur, Carbon
(c) Carbon, Nitrogen
(d) Phosphorous, Carbon

Answer : A

Question. Which is a solid fuel?
(a) Petrol
(b) Diesel
(c) Wax
(d) Wood

Answer : C

Question. In the sun, heat and light are produced by
(a)Chemical reactions
(b)Nuclear reactions
(c)Ionic reactions
(d)None of these

Answer : B

Question. The head of the safety match contains
(a) Antimony trisulphide
b Potassium Chlorate
(c) Both (a) and (b)
(d) None of these

Answer : C

Question. When the match struck against rubbing surface, red phosphorous
(a) Converts into white phosphorous
(b) Reacts with potassium chlorate
(c) Ignite antimony trisulphide
(d) None of these

Answer : A

Question. Best extinguisher for inflammable Materials is
(a) Water
(b) SO2
(c) CO2
(d) CO

Answer : C

Question. 48 CO2 is stored as a liquid in cylinder at
(a) High pressure
(b) Low pressure
(c) High temperature
(d) Low temperature

Answer : A

Question. Global warming is caused due to____ concentration of Co2 in air
(a) Decreased
(b) Increased
(c) Both (a) & (b)
(d) None of these

Answer : B

Question. Burning of coal and diesel releases
(a) NO2
(b) CO2
(c) SO2
(d) CO

Answer : C

Question.Petrol engine gives off gaseous oxides of
(a) Sulphur
(b) Nitrogen
(c) Phosphorous
(d) Carbon

Answer : B

Question. CO2 is given off by chemicals like
(a) Sodium bicarbonate
(b) Calcium sulphate
(c) Sodium sulphate
(d) Sulphuric acid

Answer : A

Question. Water is not suitable for fire involving
(a) Oil
(b) Petrol
(c) Both (a) & (b)
(d) None of these

Answer : C

Question. Amount of heat energy produced on _____combustion of 1kg of fuel is Calorific value
(a) Incomplete
(b) Complete
(c) Half
(d) None of these

Answer : B

Question. Which is better domestic fuel
(a) CNG
(b) LPG
(c) Wood
(d) Coal

Answer : B

Question. Which of the following has lower ignition temperature?
(a) Wood
(b) Paper
(c) Vegetable oil
(d) Kerosene oil

Answer : D

Question. Which one of the following is non Combustible?
(a) Stone piece
(b) Paper
(c) Straw
(d) Matchsticks

Answer : A

Question. In the presence of water, ignition Temperature of paper is-
(a) Decrease
(b) Increase
(c) Remain constant
(d) None of these

Answer : A

Question. Use of ….. in vehicle reduces pollution
(a) Petrol
(b) Diesel
(c) CNG
(d) None of these

Answer : C

Question. During the process of combustion ________is given out
(a) Heat
(b) Light
(c) Sound
(d) Both heat & light

Answer : D

Question. The most common fire extinguisher is
(a) Water
(b) CO2
(c) Oxygen
(d) Hydrogen

Answer : A

Question. Ideal fuel has ____ calorific value
(a) Low
(b) High
(c) Moderate
(d) Zero

Answer : B

Question. Calorific value gives the
(a) Fuel efficiency
(b) Amount of heat
(c) Amount of light
(d) None of these

Answer : A

Question. Calorific value is measured in
(a) Kilo joule
(b) Kilograms
(c) Kilo joule per Kg
(d) Kilometre

Answer : C

Question. Unburnt carbon particles causes
(a) Stomach infections
(b) Respiratory problems
(c) Brain infections
(d) Throat problems

Answer : B

Question. Yellow colour in the flame denotes
(a) Outermost part
(b) Middle zone
(c) Innermost zone
(d) None of these

Answer : B

Question. Good fuel is
(a) Readily available
(b) Cheap
(c) Burn easily in air
(d) All of these

Answer : D

Question. On burning fuel produces….. amount of heat
(a) Large
(b) Less
(c) Very less
(d) No heat

Answer : A

1.Which is not an example of inflammable substance?
(A) Charcoal.
(B) Petrol.
(C) Alcohol.
(D) LPG.

2.The head of the safety match contains-
(A) antimony trisulphide.
(B) potassium chlorate.
(C) Both (a) and (b).
(D) None of these.

3.When a frying pan containing cooking oil is kept for long on a burning stove then cooking oil catches fire because-
(A) Its temperature is lower than its ignition temperature.
(B) Its temperature is reached to its ignition temperature.
(C) Both (a) and (b) are correct.
(D) Neither (a) nor (b).

4.The minimum temperature at which a substance catches fire is-
(A) Melting point.
(B) Ignition temperature.
(C) Boiling point.
(D) Critical temperature.

5.Which gas is supporter of combustion?
(A) CO₂.
(B) He.
(C) O₂.
(D) Ne.

6.Find odd one out-
(A) Coal.
(B) Glass.
(C) Wood.
(D) Paper.

7.Pollution can be reduced by using-----in automobiles.
(A) Petrol.
(B) Diesel.
(C) Kerosene.
(D) CNG.

8.Combustion is a -
(A) Physical process
(B) Chemical process
(C) Both (a) and (b)
(D) None of these

9.Which of the following is not true for water?
(A) Water is the most common fire extinguisher.
(B) Water works only when things like wood and paper are on fire.
(C) Water cannot works for fire involving electrical equipments.
(D) Water is suitable for fires involving oil and petrol.

10.Which substance is used to extinguish fire involving electricity?
(A) Nitrogen.
(B) CO₂.
(C) Water.
(D) All.

11.CO₂ can be stored in cylinder in-------state at -----pressure.
(A) liquid, high.
(B) gas, high.
(C) gas, low.
(D) liquid, low.

12.Which is not the requirement for burning?
(A) Heat.
(B) O₂.
(C) Fuel.
(D) CO₂.

13.The combustion of coal dust in coal mines is-
(A) Rapid combustion.
(B) Explosion.
(C) Spontaneous combustion.
(D) None of these.

14.Find odd one out-
(A) Magnesium.
(B) Camphor.
(C) Candle.
(D) Charcoal.

15.Explosion can take place by-
(A) ignition of a combustible material.
(B) applying pressure on a combustible material.
(C) Both (a) and (b).
(D) None.

16.Flames are formed when the substance-
(A) melts during burning.
(B) vapourises during burning.
(C) boils during burning.
(D) All.

17.Which zone of the flame is least hot?
(A) Middle zone.
(B) Innermost zone.
(C) Outer zone.
(D) Luminous zone.

18.Unburnt carbon particles produced by carbon fuels cause-
(A) Abdominal diseases.
(B) Respiratory diseases.
(C) Both.
(D) None.

19.Which gas is evolved by incomplete combustion of wood or coal?
(A) CO₂.
(B) N₂.
(C) O₂.
(D) CO.

20.Calorific value of a substance is measured in-
(A) kJ/kg.
(B) Kcal.
(C) Calories.
(D) Jkg.

21.Which of the following compound has least heating value?
(A) Bio gas.
(B) Wood.
(C) Kerosene.
(D) LPG.

22.The substance having the highest Calorific value is-
(A) Hydrogen.
(B) Bio gas.
(C) LPG.
(D) CNG.

23.Which of the following is false statement?
(A) Ideal fuel is cheap and easily available.
(B) Complete combustion of a fuel gives carbon monoxide gas.
(C) Inflammable substances have very low ignition temperature.
(D) Combustion produces heat and light.

24.Which zone of the flame is used by a goldsmith?
(A) Outer zone.
(B) Middle zone.
(C) Innermost zone.
(D) None of these.

25.Global warming is the
(A) decrease in the temperature of the atmosphere of earth.
(B) moderate temperature of the atmosphere of earth.
(C) increase in the temperature of the atmosphere of earth.
(D) None.

26.Acid rain contains-
(A) Oxides of C.
(B) Oxides of S.
(C) Oxides of N.
(D) Both (b) and (c).

27.Which is not true for acid rain?
(A) It destroys crops.
(B) It melts glaciers.
(C) It damages building.
(D) It is toxic to aquatic life.

28.Which gas causes Global Warming?
(A) CO.
(B) SO₂.
(C) O₂.
(D) CO₂.

29.Dry grasses in forest catch fire in summer when-
(A) their temperature is lower than their ignition temperature.
(B) their temperature is reached near their ignition temperature.
(C) Both are correct.
(D) None of these.

30.Which is not the example of combustion?
(A) Sodium burns in air.
(B) Spontaneous reaction of coal dust in coal mines.
(C) Reaction of food in our body.
(D) Reaction in the sun.

31.A burner of a gas stove gives yellow flame, it indicates-
(A) Incomplete combustion.
(B) Complete combustion.
(C) Both.
(D) None.

32.Match the column 'I' with Column 'II'
Column 'I'                       Column 'II'
i. Oxygen                         A. Fuel
ii. Carbon dioxide            B. Combustion
iii. Food                           C. LPG
iv. Inflammable D. Fire extinguisher
(A) i-B, ii-A, iii-C, iv-D
(B) i-B, ii-A, iii-D, iv-C
(C) i-B, ii-D, iii-A, iv-C
(D) i-A, ii-B, iii-C, iv-D

33.Find the odd one out.
(A) CO₂.
(B) CH₄.
(C) Oxygen.
(D) Water vapours.

34.Which is true for wood?
(A) It is not easily available.
(B) It produces a large amount of heat on burning.
(C) It does not give smoke on burning.
(D) It leaves behind ash after burning.

35.Kavita, Mahima and Shreya were doing an experiment in which water was to be heated in a beaker. Kavita kept the beaker innermost of the wick in black part of the candle flame.
Mahima kept the beaker near the wick in the yellow part and Shreya kept the beaker in the outermost part of the flame. Whose water will get heated in a shorter time?
(A) Kavita.
(B) Mahima.
(C) Shreya.
(D) Both Mahima and Shreya.

36.The process of combustion produces-
(A) Heat.
(B) Light.
(C) Both (a) and (b).
(D) None.

37.Which of the following is the most ideal fuel?
(A) Wood.
(B) Kerosene.
(C) LPG.
(D) None.

38.Match the column 'I' with Column 'II'
Column 'I'                            Column 'II'
1. CNG                     A. Combustible substances
2. LPG                      B. Inflammable substances
3. Wood, Charcoal     C. Cleaner Fuel
4. Alcohol, Petrol           Liquid Fuel
(A) 1-C, 2-D, 3-A, 4-B
B) 1-C, 2-D, 3-B, 4-A
(C) 1-D, 2-C, 3-B, 4-A
D) 1-C, 2-A, 3-B, 4-D

39.CO₂ can be produced by -
(A) Washing soda.
(B) Baking soda.
(C) Potassium bicarbonate.
(D) Both (b) and (c).

40.Name two fuels which are used for running automobiles.

41.A circular blackish ring on the glass plate indicates-
(A) Complete combustion.
(B) Dark zone of the flame.
(C) Non-luminous zone.
(D) Luminous zone.

42.Define combustion.

43.Write a difference between burning of a candle and the burning of coal.

44.What do you understand by combustible substances or fuels?

45.Why is food regarded as a fuel for our body?

46.Is burning of magnesium combustion?

47.Give two examples of non-combustible substances.

48.What is essential for combustion?

49.What do you mean by ignition temperature?

50.Does a matchstick burn by itself?

51.What is the composition of the head of the matchstick?

52.Which type of pollution occurs on burning wood?

53.Name a liquid fuel which is used in homes?

54.Write the full forms of-
(a) CNG (b) LPG

55.When a burning charcoal piece is covered with a glass jar then the burning of the piece stops, why?

56.Which will get fire first coal or kerosene?

57.Which is the most common fire extinguisher?

58.Which poisonous gas is produced due to incomplete combustion of a fuel?

59.Name the substance used to extinguish fire involving electrical equipments.

60.Which of the following compound has least heating value?
(A) Bio gas. (B) Wood. (C) Kerosene. (D) LPG.

61.What are inflammable substances?

62.What would you do when the clothes of a person catch fire?

63.How is CO₂ able to control fire?

64.What do you understand by Explosion?

65.Which zone of a flame does a goldsmith use for melting gold and silver and why?

66.How can water boil in a paper cup without burning it?

67.What are the three zones of a flame? Draw a labelled diagram of a candle flame.

68.Why does the matchstick start burning on rubbing it on the side of the matchbox?

69.What are the essential requirements for producing fire? On which principle the fire extinguisher works?

70.Give reasons-
(i) LPG is a better domestic fuel than wood.
(iii) Water is not used to control fires involving electrical equipment.

71.Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.

72.Explain how water is able to control fires?

73.Definea.
Spontaneous combustion. b. Rapid combustion.

74.(i) What is calorific value? Write its unit.
(ii) In an experiment 4.5 kg of a fuel was completely burnt. The heat produced was measured to be 180,000 kJ. Calculate the calorific value of the fuel.

75.Why is it difficult to burn a heap of green leaves but dry leaves catch fire easily?

76.What do you understand by Global Warming? Give any two consequences of Global Warming.

77.What are the characteristics of an ideal fuel?

78.What is acid rain. Write its harmful effects.

79.How will you show that for a substance to burn, it is essential to reach its ignition temperature?

1. Define Fuel. Give examples of solid, liquid and gaseous fuels.

2. Differentiate between combustible and non-combustible substances with two examples of each kind.

3. Why does a candle stop burning when covered with a glass tumbler ?

4. How is spontaneous combustion different from explosion?

5. Special care should be taken to store kerosene oil. Give reason.

6. Why is L.P.G labeled as inflammable substance?

7. How does water help to extinguish fire?

8. Underline the substances which will produce flame on burning and why?

Charcoal ,molten wax, paper, coal, mustard oil

9. Draw a well labeled diagram of the flame of a candle and answer the following Questions:

(a) Which zone is luminous and why ?

(b) Why is the innermost zone grey in colour and the coldest zone ?

(c) Which zone is called the zone of complete combustion and why?

10. Calorific value of wood is approx.17000-22000kj/kg. What does it mean?

11. Why is it dangerous to burn coal in a closed room?

12. Write any 4 characteristics of good fuel.

13. Name the gases which lead to formation of acid rain.

14. In an experiment 10 Kg of a fuel produced 200,000 KJ 0f heat . Calculate the calorific value of the fuel.

15. How does CO₂ help in fire fighting?

1. Define Fuel. Give examples of solid, liquid and gaseous fuels.

2. Differentiate between combustible and non-combustible substances with two examples of each kind.

3. Why does a candle stop burning when covered with a glass tumbler ?

4. How is spontaneous combustion different from explosion?

5. Special care should be taken to store kerosene oil. Give reason.

6. Why is L.P.G labeled as inflammable substance?

7. How does water help to extinguish fire?

8. Underline the substances which will produce flame on burning and why?

Charcoal ,molten wax, paper, coal, mustard oil

9. Draw a well labeled diagram of the flame of a candle and answer the following

 

Questions:

(a) Which zone is luminous and why ?

(b) Why is the innermost zone grey in colour and the coldest zone ?

(c) Which zone is called the zone of complete combustion and why?

10. Calorific value of wood is approx.17000-22000kj/kg. What does it mean?

11. Why is it dangerous to burn coal in a closed room?

12. Write any 4 characteristics of good fuel.

13. Name the gases which lead to formation of acid rain.

14. In an experiment 10 Kg of a fuel produced 200,000 KJ 0f heat . Calculate the calorific value of the fuel.

15. How does CO₂ help in fire fighting?

1.Define Fuel. Give examples of solid,liquid and gaseous fuels.

2.Differentiate between combustible and non-combustible substances with two examples of each kind.

3.Why does a candle stop burning when covered with a glass tumbler ?

4.How is spontaneous combustion different from explosion?

5.Special care should be taken to store kerosene oil.Give reason.

6.Why is L.P.G labeled as inflammable substance?

7.How does water help to extinguish fire?

8.Underline the substances which will produce flame on burning and why?

Charcoal ,molten wax, paper, coal, mustard oil

9. Draw a well labeled diagram for the flame of a candle and answer the following

 

Questions:

(a)Which zone is luminous and why ?

(b)Why is the innermost zone grey in colour and the coldest zone ?

(c)Which zone is called the zone of complete combustion and why?

10. Calorific value of wood is approx.17000-22000kj/kg .what does it mean?

11. Why is it dangerous to burn coal in a closed room?

12. Write any 4 characteristics of good fuel .

13. Name the gases which lead to formation of acid rain.

14. In an experiment 10 Kg of a fuel produced 200,000 KJ 0f heat . Calculate the calorific value of the fuel.

I5.How does CO2 help in fire fighting?

Q.1. Answer the following questions in 30- 40 words:

a-What is meant by luminous and nonluminous flames?

b-Name two damaging effects of burning of coal and petroleum.

c-Mention any two characteristics that you would consider for selecting the most ideal fuel.

d-What is acid rain?How does it affect the iron structures?

Q.2. Answer the following questions in 80- 100 words:

a-What is a combustible substance?Give suitable examples.

b-Draw a labelled diagram showing four zones of a candle flame.

c-An electric spark is passed between two electrodes placed near each other inside a tightly closed tin can full of petrol/diesel, will the petrol/diesel catch fire? Give reason in support of your answer.

d-How are fuels classified ? Give two examples of each class.

e-Name the various pollutants produced by the combustion of fossil fuels . Also mention their harmful effects.

Q.3. Define the following terms

a-Ignition Temperature

b-Complete Combustion

c-Luminous flame

d-Fuels

e-Characteristics of an Ideal fuel

Q.4.Write one word for the following

a-The process in which a substance combines with oxygen producing heat and light.

b-The combination reaction that takes place in the presence of insufficient air of another substance.

Q.5.Match the following:

a- combustible substance i-Fire fighting

b-Carbon dioxide ii-Fuels

c-Hydrocarbons iii-Complete combustion

d-Hottest part of the candle flame iv-Kilo joule per gram

e-Calorific value v-Paper

Q.6. Choose the correct answer:

a-Which of the following has the lowest ignition temperature?

i-Petrol ii-Kerosene iii-coal iv-LPG

b-The substance having the highest calorific value is

i-LPG ii-Hydrogen iii-Oxygen iv-coal gas

c-Which of the following gives a pollution free environment when burnt

i-Dung cake ii-Kerosene iii-Wood iv-Biogas

d-What is produced during combustion of substance

i-Light ii-Heat iii-Both heat and light iv-None of the above