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Combustion and Flame Chapter 6 Science Class 8 Extra Questions




In this page we have Combustion and Flame Class 8 Extra Questions Chapter 6 Science . This included Fill in the blanks, Match the column, Short answer type , True and false and Jumbled word questions.Hope you like them and do not forget to like , social share and comment at the end of the page.

Very Short answer type questions

Question 1
Very short answer type questions:
(i) Give two examples of secondary fuels.
(ii) What is the calorific value of diesel?
(iii) What is global warming?
(iv) Which gaseous is used in our homes for cooking?
(v) What is a flame?

Answer

i.Petrol and diesel.
ii.45,000 kilojoules per kilograms
iii.The excessive production of carbon dioxide gas causes the over-heating condition. This over-heating condition is called global warming.
iv.Liquid Petroleum Gas
v.The flame is a region where the combustion takes place.


Question 2
Short answer type questions:
(i) What is a fire extinguisher? Write two types of fire extinguishers.
(ii) What is calorific value? Write its SI unit.
(iii) What are non-renewable fuels? Give two examples.
(iv) What are gaseous fuels? Give two examples.
(v) What is slow combustion? Give two examples.

Answer

(i)The fire extinguisher is a portable apparatus used to control the level of unwanted fire at a certain place. Two types of fire extinguishers are- carbon dioxide and soda-acid.
(ii)The efficiency of fuel that calculates the heat released when one gram of fuel burns completely in oxygen.
(iii)The fuels that are present in a limited amount are called non-renewable fuels. Coal and petroleum are two examples of non-renewable fuels.
(iv)The fuels that are found in the form of gaseous state are called gaseous fuels. Hydrogen and coal gas are two examples of gaseous fuels.
(v) The combustion that takes place slowly at a low temperature is called slow combustion. Digestion and rustling are two examples of slow combustion.


Short answer type questions/HOTS:

Question 3
Ruby lights the burner with a lighter and noticed that the flame rises blue in colour. Why the colour of the flame is blue?

Answer

The colour of the flame is blue because the air hole of the burner opens which means it provides sufficient supply of oxygen.


Question 4
Why the luminous zone is also called incomplete combustion?

Answer

Luminous zone is a middle zone or zone of incomplete combustion because it takes place in the presence of limited air.


Question 5
Illustrate some brief description about solid fuels, liquid fuel and gaseous fuels.

Answer

Brief description about solid fuels, liquid fuels and gaseous fuels are given below: -


Question 6
Write three characteristics of an ideal fuel.

Answer

The three characteristics of an ideal fuel are as follows: -

  • High calorific value.
  • Moderate ignition temperature.
  • Easy to store and transport.


Question 7
What happen if anyone inhale carbon monoxide gas?

Answer

If anyone inhales carbon monoxide, it mixes with his/her haemoglobin and produces carboxyhaemoglobin which decreases the amount of oxygen carrying by the blood and causes respiratory disorders, headache, dizziness and fatigue.


Question 8
Which gas is responsible of global warming and why?

Answer

Carbon dioxide gas is responsible for increasing global warming because the excess amount of CO2 traps the heat produced by the sunrays and prevents it from reflecting back that causes the over-heating condition. This over-heating condition is called global warming.


Question 9
Which compound is present in smoke released by the vehicles and what happen if the smoke produces in an enormous value?

Answer

The smoke released by the vehicles contains lead compounds that are poisonous. Therefore, the excessive releasing of the smoke populated the environment and continuous inhalation can cause respiratory disorders including cancer.


Question 10
Write a general equation of chemical reaction for complete combustion.

Answer

The general equation of chemical reaction for complete combustion is: -


Long answer type questions:


Question 11
Explain the zones of candle flame and also draw a well-labelled diagram.

Answer

All three zones of candle flame are explained in details below: -
Combustion and Flame Class 8 Extra Questions Chapter 6 Science
Combustion and Flame Class 8 Extra Questions Chapter 6 Science


Question 12
Write a short note about soda-fire extinguisher? Also draw its well-labelled diagram.

Answer

Soda-fire extinguisher has a metallic cylinder that contains a saturated solution of sodium bicarbonate. A glass bottle filled with a concentrated sulphuric acid attached to the cap of the metal cylinder. The connection between the sodium bicarbonate and sulphuric acid produces carbon dioxide when anyone struck the knob. Afterwards, carbon dioxide forms a blanket over the burning area that cut-off the interaction between the fire and air resulting the excavation of fire.
Combustion and Flame Class 8 Extra Questions Chapter 6 Science


Summary

This Combustion and Flame Chapter 6 Science Class 8 Extra Questions is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.



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