Combustion

Q.

Phosphorus reacts with oxygen to form-

1. phosphorus oxide

2. phosphorus dioxide

3. phosphorus pentoxide

4. phosphorus trioxide

Q. During combustion, energy is released in the form of:

1. Heat only
2. Light only
3. Light and heat
4. Sound

Q.

The gas present in the air which helps in burning is

1. Oxygen

2. Nitrogen

3. Carbon dioxide

4. None of these

Q.

Fuel + Oxygen (from air) $\to$ Carbon dioxide + Water vapour + Heat.
This reaction shows ___ .

1. transpiration

2. fuel fixation

3. corrosion

4. combustion

Q. Phosphorus when reacted with present in the air forms phosphorus pentoxide.

1. carbon dioxide
2. oxygen
3. water vapour

Q.

Which of the following are products of combustion?

1. Carbon dioxide

2. Nitrogen

3. Water

4. Energy

Q. When a fuel is burned in air, it releases heat energy, water vapour and gas.

1. oxygen
2. carbon dioxide
3. nitrogen

Q.

State true or false.
Air, containing oxygen, is present all around us. We know that oxygen supports burning. So logically, in the presence of oxygen, even a small fire should burn down everything.

1. True

2. False

Q.

Which of the following is common for both respiration and combustion?

1. A small amount of energy is released in both the processes.

2. Both are fast processes.

3. They are natural processes.

4. Carbon dioxide and water vapour are formed in both the processes.

Q.

Though nitrogen does not support combustion, it controls the rate of combustion. Give reasons for the statement.

Q. name two products formed by the burning of candle in air

Q.

If 1000kg of coal is burnt what is the output

Q.

Which gas is used in hospitals for storing and preventing blood and tissues?

Q.

The main source of water vapor is the burning of_______ which produces carbon dioxide and water vapor

Q.

During the process of combustion, which of the following forms of energy is released?

1. Heat energy

2. Electric energy

3. Light energy

4. All of the above

Q.

Among the gases present in air, which one supports combustion?

1. Nitrogen

2. Carbon dioxide

3. Oxygen

4. Water vapour

Q.

Name the constituent of air which is essential for combustion and respiration.

Q.

11. State the precautions while preparing oxygen in the laboratory?

Q.

For the easy combustion of coal, air has to be blown around it.

1. False

2. True

Q.

Combustion removes carbon dioxide from the air.

1. True
2. False

Q.

Antoine Lavoisier, a French scientist, first established that air contains more than one gas.

1. True
2. False

Q.

State two similarities and two differences between respiration and burning.

Q.

Define the following terms: Combustion.

Q. Gas X has the properties as given below:
1) Colourless and odourless
2) neither burns nor supports burning
3) extinguishes a burning fire
4) minor component of air.
Based on the above characteristics, identify X.

1. Nitrogen
2. Oxygen
3. Carbon dioxide

Q.

Oxygen is chemically an active gas. Give reason.

Q.

Now that they all knew so much about air, they shifted their discussion to a more specific topic; Oxygen. Sam being the eldest convinced both John and Kenneth that to talk about oxygen. Our life line!

Kenneth: Yes sure we should know more about oxygen.

John: Now I remember what Sam said, my teacher also said the same thing, that oxygen supports combustion.

Kenneth: That means oxygen supports burning.

Sam: Now this brings me to another question. Since we know that oxygen supports burning. There is so much oxygen present in air, why don't we all get burnt then?

Kenneth: Nitrogen is present in much larger quantity than oxygen in air around us and since nitrogen does not supports burning, it dilutes oxygen to an extent that it does not burn everything.

State whether Kenneth's answer is true or false.

1. True
2. False

Q.

The presence of ________ in the air controls the process of burning.

Q.

In an experiment, a lighter is brought in contact with a funnel contaning a gas. The lighter burns with a bright flame. Presence of which gas is confirmed in this experiment?

1. Carbon dioxide

2. Oxygen

3. Water vapour

4. Argon

Q.

State if the following statements are true or false. Rewrite the false statements correctly.

The burning of fuels releases oxygen into the air.

1. True
2. False

Q.

Which of the following factors are essential for a fire to ignite?

1. Heat

2. Air (oxygen)

3. Fuel

4. All of these