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Saturday, August 11, 2012

CHEMISTRY-8th Combustion and Flame Assignment /Worksheet

CHEMISTRY VIII 8th Combustion and Flame Assignment /Worksheet
Q.1 Name a few fuels used in our homes.
Q.2 Name a few fuels used in trade and industry.
Q.3 What fuels are used for running automobiles?
Q.4 What is the difference between the burning of a candle and burning of a fuel like coal?
Q.5 What is combustion?
Q.6 Define a fuel?
Q.7 (i) What are the essential condition required for combustion?
     (ii) What is the essential condition required for extinguishing fire?
Q.8 What are inflammable substance?
Q.9 In what form is LPG stored in cylinders?
Q.10 Name the most common fire extinguisher?
Q.11 Water is not suitable for fires involving electrical equipment oil and petrol. Why?
Q.12 Explain how CO2 is able to control fires?
Q.13 What are the requisites (qualities) of a good (ideal) fuel?
Q.14 Explain the following terms:-  (i) Global warming (ii) Acid rain
Q.15 Suppose you are asked to boil a given quantity of water using cow dung cake, coal and LPG as fuels. Which fuel would you prefer? Give your reason.
Q.16 Define calorific value of a fuel. Though hydrogen has got highest calorific value but it is not used as a domestic fuel. Why?
Q.17 Make a labeled diagram of a candle flame.
Q.18 Name various types of combustion. Give example of each type?
Q.19 In an experiment 10 Kg of a fuel  produced 200,000 KJ 0f heat . Calculate the calorific value of the fuel.
Q.20.How does CO2 help in fire fighting?

7 comments:

Anonymous said...

These were quite helpful. Wonderful job done! Wanted some Class 7 worksheets as well!

Regards
Arunava Das
Chemistry Teacher
@ DPS Siliguri

J.Sunil Sir said...

Though hydrogen has got highest calorific value but it is not used as a domestic fuel. Why?

Hydrogen has a very high calorific value and unlike coal, petroleum etc is a clean fuel. However, it is not used as a fuel in day to day life because :
(a) It is highly flammable and is therefore extremely explosive.
(b) It is difficult to store

J.Sunil Sir said...

What is the difference between the burning of a candle and burning of a fuel like coal?

Candle burns with a flame but coal does not burns with a flame also coal is a carbon product and its burning is harmful for environment but candle is made from wax its burning is not as much harmful as burning of coal

J.Sunil Sir said...

Food is a fuel for the body. Justify this statement.


Ans: Food is a fuel for our body because inside our body food is broken down into simpler form by reaction with oxygen and with the release of heat and energy.

J.Sunil Sir said...

Why we say increasing fuel consumption has harmful effects on environment?


Increasing fuel consumption has harmful effects on environment because:

Carbon fuels like wood, coal and petroleum releases unburnt carbon particles that are dangerous pollutants causing diseases like asthma and respiratory disorders
Incomplete combustion of these fuel releases a very poisonous gas carbon monoxide
Release of carbon dioxide gas by combustion of fuels is becoming one of the cause of global warming

J.Sunil Sir said...

What is flame?

Ans:
A flame is the visible, gaseous part of a fire. The substance which vaporise during burning give flames, It is caused by a highly exothermic reaction taking place in a thin zone.

J.Sunil Sir said...

. Explain how the use of CNG in automobiles has reduced pollution
in our cities.

Answer : Our cities generally have high numbers of automobiles vehicals. The use of
diesel and petrol as fuels in automobiles is a major cause of air pollution to day. During
combustion, these fuel release unburnt carbon particles. These fine particles are
dangerous pollutants causing respiratory diseases, such as asthma.Incomplete
combustion of these fuels gives carbon monoxide gas. It is a very poisonous
gas.Combustion of most fuels releases carbon dioxide in the environment. Increased
emission of carbon dioxide in the air is one of the major cause for global warming.
The use of diesel and petrol as fuels in automobiles is being replaced by CNG
(Compressed Natural Gas), because CNG produces the harmful products in very small
amounts. CNG is a cleaner fuel. It has high fuel efficiency. Hence use of CNG in
automobiles has reduced pollution in our cities to a noticable extent

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