Combustion

Q.

Write the combustion reaction of methane.

Q.

What are five examples of combustion in your everyday life?

Q.

Oil is more dense than water.

1. False

2. True

Q.

What happens when Carbon burns in air? Write a balanced equation.

Q.

Give 15 examples of combustible substances

Q.

What is the significance of combustion as an oxidation reaction?

Q.

It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain

Q.

Write the full form of PCRA.

Q. Which of the following has the lowest ignition temperature?

1. Wood
2. Paper
3. Kerosene
4. Plastic

Q.

Explain the different zones observed in a candle flame. Which one of them is the hottest zone? [5 MARKS]

Q.

Describe the various zones of a candle flame.

Q.

Where is natural gas not found in India?

1. Rajasthan

2. Maharashtra

3. All of the above options are correct.

4. Tripura

Q. What is coal gas? Mention its uses.

Q. Explain how petroleum and natural gas are formed.

Q. On what principle is a fire extinguisher based on?

Q. Difference between Luminous and non luminous zone ?

Q.

The colour of outer zone of a candle flame is ___.

Q. Incomplete combustion results in the formation of:

1. Carbon Monoxide
2. Water
3. Hydrogen
4. Oxygen

Q.

If a person’s clothes catch fire, the best way to extinguish the fire is to:

1. Throw water on the clothes.

2. Use the fire extinguisher.

3. Cover the person with a woolen blanket.

4. Cover the person with a polythene sheet.

Q.

Why is Sun burning even though there is no oxygen ???

Q.

Three liquids are taken: mercury, water and oil. If all are put in the same container, then what is the order in which they form layers starting from bottom?

1. Water, Mercury, Oil

2. Oil, Water, Mercury

3. Mercury, Water, Oil

4. Mercury, Oil, Water

Q.

Carbon dioxide and water are the main products of combustion.

1. True
2. False

Q.

Which zone of candle flame has the least and highest temperature? [2 MARKS]

Q. Middle zone of a candle falme burns with a yellow flame.

Q.

Methane is used as fuel. Give one reason

Q. The blue colour of flame is due to burning of carbon monoxide.

1. False
2. True

Q. The colour of the innermost zone of a candle flame is___.

1. orange
2. yellow
3. black
4. blue

Q.

Which of the following is not a combustible substance?

1. camphor

2. glass

3. straw

4. alcohol

Q.

Why is carbon dioxide used in fire extinguishers?

Q. A candle flame consists of how many zones?

1. one
2. two
3. three
4. four