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Important questions on Combustion

What is the factor that differentiates between combustion and burning?

A

Amount of oxygen used

B

Environment

C

Material

D

None of the above

View Answer

They are different with respect to the combustion is done in a fixed amount of oxygen while in burning it has the access of infinite amount of oxygen (done in open).
Hence option (A) is correct.

Hence, the correct option is

In combustion, heat is ______________.

A

absorbed

B

released

C

reduced

D

All of the above

View Answer

Combustion is a high temp exothermic reaction between fuel and oxidant usually atmospheric oxygen i.e. heat is given out.

A chemical process in which a substance reacts with oxygen to give off heat is called?

A

Ignition

B

Combustion

C

Conduction

D

None of the above

View Answer

A chemical process in which a substance reacts with oxygen to give off heat is called combustion.

When fuel is added to the exhaust (burnt) gases in a jet engine combustion takes place. Some facts are mentioned here about this combustion. Pick the false one?

A

It increases the intake of oxygen from the air

B

It reduces fuel consumption

C

It gives additional thrust

D

It is known as 'after burning'

View Answer

When fuel is added to exhaust gases in a jet, engine combustion takes place to release energy so that it gives additional thrust to increase efficiency of the engine.

Combustion is a:

A

physical process

B

chemical process

C

biological process

D

mechanical process

View Answer

The chemical mechanism of their combustion is not yet clear, probably because oxidation of carbon monoxide, a reaction that is part of the combustion of practically all-natural fuels, usually occurs in the presence of hydrogen or hydrogen compounds.

Hence, combustion is a chemical process.

Quality that is not suitable for a fuel is ________ .

A

high calorific value with ignition temperature that is well above the normal room temperature

B

low rate of evaporation at room temperature

C

carbon particles are expelled with smoke

D

low content of non-combustibles

View Answer

Quality that is not suitable for fuel is carbon particles are expelled with smoke and causes air pollution. 

In a Bunsen's burner, use is made of

A

Surface tension

B

Suction Pump

C

Boyle's Law

D

Bernoulli's theorem

E

Archmedes' principle

View Answer

Which among the following has the highest calorific value ?

A

Petrol

B

Kerosene

C

Ethanol

D

Wood

View Answer

Petrol have highest calorific value of about 45.8 MJ/kg.

Which of the following is a combustion reaction?

A

Boiling of water

B

Melting of wax

C

Burning of petrol

D

None of these

View Answer

Combustion reactions always involve molecular oxygen . Anytime anything burns (in the usual sense), it is a combustion reaction. Combustion reactions are almost always exothermic (i.e., they give off heat). For example: When wood burns, it must do so in the presence of and a lot of heat is produced.

In combustion, the substance reacts with ___________.

A

hydrogen

B

oxygen

C

nitrogen

D

carbon dioxide

View Answer

Combustion is a high temp exothermic reaction between fuel and oxidant usually atmospheric oxygen.

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