Tag: fuels

Questions Related to fuels

Combustion of most fuels releases $CO _2$ causing:

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. Water pollution

  2. Global warming

  3. Acid rain

  4. All of above

Show answer
Correct Option: B
Explanation:

Combustion of most fuels releases $CO _2$ causing global warming. Global warming is the rise in the temperature of the atmosphere of the earth. 

_____ is any material that can be made to react so that it releases chemical or nuclear energy as heat.

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. Fossil fuel

  2. Fuel

  3. Oil

  4. All of the above

Show answer
Correct Option: B
Explanation:

A fuel is any material that can be made to react so that it releases chemical or nuclear energy as heat or to be used for work. The heat energy released by reactions of fuels is converted into mechanical energy via a heat engine.

What is an ideal fuel?

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. It has high calorific value

  2. It is cheap

  3. It is readily combustible

  4. All of the above

Show answer
Correct Option: D
Explanation:

An ideal fuel is cheap, readily available, easy to transport and readily combustible. It has high calorific value. It does not produce gases or residues that pollute environment.

The ignition temperature of an ideal fuel should _____________.

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. Lowest

  2. Highest

  3. Neither too high nor too low

  4. None of the above

Show answer
Correct Option: C
Explanation:

Ideal fuel should have a proper ignition temperature, so that it can be burned easily. The ignition temperature of an ideal fuel should neither be too low nor too high. If the ignition temperature of the fuel is very low, then the fuel will catch fire too easily and hence it will be very unsafe to use it. On the other hand, if the ignition temperature is too high, then it will be very difficult to light the fuel.

A good fuel has these qualities:

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. should have high calorific value

  2. should be costly

  3. should cause any pollution

  4. should be easy to transport

Show answer
Correct Option: A,D
Explanation:

A good fuel should have high calorific value, should be cheap, should not cause any pollution and should be easy to transport.

Kerosene is mixture of?

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. Alkanes

  2. Aromatic compounds

  3. Alcohols

  4. Aliphatic acids

Show answer
Correct Option: A
Explanation:

 the major components of all kerosenes are branched and straight chain alkanes and naphthenes (cycloalkanes), which normally account for at least $70\%$ by volume

Statement: Combustion can take place at all temperatures less than an ignition temperature.


State whether the given statement is true or false.

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

The minimum temperature at which a substance starts to burn is called its ignition temperature. Different fuels have different ignition temperatures.  Low ignition temperature means highly inflammable. For combustion, ignition temperature should at least be achieved. Substance starts burning only at a temperature equal to ignition temperature or more than it.


Hence, the given statement is $false$

Fuel efficiency is measured as 

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. Its calorific value

  2. Amount of heat produced by fuel per unit mass or volume

  3. $kJ/Kg$

  4. None of these

Show answer
Correct Option: A,B,C
Explanation:

Fuel efficieny can be measured as the amount of heat that is required by 1kg of fuel during combustion.  It is known as calorific value of the fuel.  The unit of measuring fuel efficieny is kJ/Kg.

Which of the following has lowest ignition temperature ?

evs how to save fuel fuels fuel and effects of burning fuel study of combustion

  1. LPG

  2. Petrol

  3. Coal

  4. Kerosene

Show answer
Correct Option: A

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that __________.

chemistry combustion and flame fuels fuel and effects of burning fuel study of combustion

  1. the food is not cooked completely

  2. the fuel is not burning completely

  3. the fuel is wet

  4. all of the above

Show answer
Correct Option: B
Explanation:

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that the fuel is not burning completely. When the fuel burns completely giving a blue flame, the bottom of the vessel remains clean. 


When the fuel does not burn completely then a sooty flame appears which makes the bottom of the utensil black. It is due to the air holes, which are getting blocked and the fuel does not burn completely.