Burning Behaviour of Substances

Q.

The substances which vapourise during burning give flames.

1. True

2. False

Q. What is the main chemical component present in matchbox strips?

1. Potassium chlorate
2. White phosphorus
3. Red phosphorus
4. Carbon

Q.

Coal is a ___ combustible substance.

1. solid

2. liquid

3. gas

4. None of the above

Q. Which among the following substances does not burn with a flame?

1. Camphor
2. Candle
3. Dry Grass
4. Coal

Q. Substances which ______ during burning produce flames.

1. freezes
2. melts
3. solidifies
4. vapourise

Q. Question 9
It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain.

Q. Give reasons. ​
(a) Water is not used to control fires involving electrical equipment.​
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminum pipe does not.

Q. Question 16
Fill in the blanks in the following sentences.
(a) A ____________ process in which a substance reacts with __________ to give off heat is called combustion.

(b) When the clothes of a person catch __________, the person is covered with a __________ to extinguish fire.

(c) The __________ temperature at which a substance catches fire is called its ignition temperature.

(d) The substances which have very ________________ ignition temperature and can easily catch fire with a flame are called __________ substances.

(e) The substances which vapourise during __________, give flame.

Q. A flame is formed during burning of a substance due to:

1. Fire could be used to cook food

2. Fire could provide heat

3. Fire provided a portable form of light and could protect from predators

4. All the above options are correct.

Q.

The substances, which vapourise during burning, gives flame. (True or False). Also write the false statements in their correct form.

1. True
2. False

Q. Firefighters’ uniforms have a coating of to make them fire retardant.

1. melamine
2. silk
3. rayon

Q. Which among the following will catch fire easily at room temperature?

1. Copper wire
2. Plastic
3. Spirit
4. Water

Q. Statement I: Charcoal burns with flames.
Statement II: Charcoal doesn't vapourise while burning.

1. Statement I is false but statement II is true
2. Both statements are true
3. Both statements are false
4. Statement I is true but statement II is false

Q.

5 uses of non metals

Q. Why a newspaper or stick lying in the open does not catch fire on its own?

Q. Every substance that burns produces flames.

1. True

2. False

Q. do all gases burn with a flame

Q. Which among the following substances does not burn with a flame?

1. Camphor
2. Dry Grass
3. Candle
4. Coal

Q.

In modern matches, why do we need to rub the bulb on the matchbox?

1. Sulphur

2. Potassium Chlorate

3. Both Potassium Chlorate and Sulphur

4. Nitrogen

Q. Statement I: Charcoal burns with flames.
Statement II: Charcoal doesn't vapourise while burning.

1. Statement I is true but statement II is false
2. Statement I is false but statement II is true
3. Both statements are true
4. Both statements are false

Q.

What are fine black particles, chiefly composed of carbon, produced by incomplete combustion of coal, oil, wood, or other fuels called?

1. Soot

2. Fume

3. Fog

4. Smog

Q. Which among the following does not produce a flame on burning?

1. Plastic
2. Candle
3. Kerosene oil
4. Camphor

Q. The outermost zone is the hottest part of the flame.

1. True
2. False

Q. Fill in the blanks with the correct properties of different zones of a flame.​

Q. Which of the following substances will burn with a flame?

1. Candle
2. Coal
3. Synthetic fibres
4. Camphor
5. Plastic
6. Kerosene stove
7. LPG
8. Charcoal
9. Magnesium

Q. Which among the following does not produce a flame on burning?

1. Plastic
2. Candle
3. Camphor
4. Kerosene oil

Q. Arrange the steps involved in the production of fire in the correct order.

1. Burning of fuel
2. Ignition temperature attained
3. Reaction with air
4. Release of energy

Q. Which of the following substances will burn with a flame?

1. Candle
2. Magnesium
3. Camphor
4. Kerosene stove
5. Synthetic fibres
6. Charcoal
7. LPG
8. Coal
9. Plastic