Burning And Combustion

Q.

Name the three types of combustion and give two examples of each.

Q.

Nitrogen controls the extent of burning.

1. True

2. False

Q. Which of the following gas supports combustion?

1. Argon
2. Oxygen
3. Nitrogen
4. Neon

Q.

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

Q. Burning of fuel produces lot of heat energy.

1. True
2. False

Q.

Write a note on oxyhydrogen flame.

Q.

Why is the leakage of LPG detected easily although it is odourless? State the steps to be taken in case leakage is detected in the kitchen.

Q. Conversion of free nitrogen into it's compounds is called .

1. nitrogen fixation
2. nitrification
3. assimilation

Q. If one of the three essential elements of the fire triangle is removed, the fire will:

1. increase
2. decrease
3. Stop
4. Continue

Q.

Automobile exhaust gas that causes major respiratory problem is:

1. CO

2. CH₄

3. NO₂

4. Chlorine

Q. The setting of cement is

1. enzyme catalyzed reaction
2. Rapid combustion reaction
3. exothermic reaction
4. endothermic reaction

Q.

3. State one relevant observation for the following reaction.
Burning of ammonia in air.

Q.

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

1. True
2. False

Q. Burning of fossil fuels release _______ gas along with heat and light.

1. nitrogen dioxide
2. oxygen
3. hydrogen
4. carbon dioxide

Q.

Q.

When a metal reacts with oxygen _____ is formed.

1. Metal oxide

2. Metal hydride

Q.

Which is better fuel between A and B - study the table to give the answer.

Fuel	Calorific value	Ignition temperature	Products obtained on burning
A	$75\raisebox{1ex}{$kJ$}\!\left/ \!\raisebox{-1ex}{$kg$}\right.$	${25}^{\circ }C$	${\mathrm{CO}}_2,\mathrm{CO},\mathrm{ASH}$
B	$50\raisebox{1ex}{$kJ$}\!\left/ \!\raisebox{-1ex}{$kg$}\right.$	${75}^{\circ }C$	${\mathrm{CO}}_2$

Q. Assertion :It is dangerous to burn methane in an insufficient supply of air. Reason: Methane creates carbon dioxide and suffocates you, or worse, partial combustion produces carbon monoxide which, if you inhale it, ties up your haeamoglobin and prevents it carrying oxygen around your body

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Distinguish between combustion and rusting on the basis of rate , nature of the reaction and residue.

Q. When a person is caught with fire, he or she is wrapped in a thick blanket so as to

1. cut off the oxygen supply
2. cut off the nitrogen supply
3. cut off the carbon dioxide supply
4. keep the body cool

Q.

After Kenneth's reply, John could remember that he had seen in movies that people cover themselves in blankets during fires. He asked Kenneth 'how would you explain this activity?' Is it true that blankets save us from fires? Can you give us a reason.

Kenneth: Yes blankets save us from fires. But I don't know the exact reason. Maybe Sam can help us.

John: Yes Sam you must be knowing this.

Sam: Yes, I know........................

Which of the following can be Sam's answer?

1. Blankets cut off the supply of nitrogen to fire and hence stop fire from spreading.
2. Blankets cut off the supply of carbon dioxide to fire and hence stop fire from spreading.
3. Blankets cut off the supply of oxygen to fire and hence stop fire from spreading.
4. Blankets cut off the supply of water vapours to fire and hence stop fire from spreading.

Q.

___________________flame is used for cutting and welding.

Q. How will you prove that air supports burning?

Q. Name the product formed when substance 'X' burns in air.

1. Carbon dioxide
2. Water vapor
3. Both $A$ and $B$
4. Carbon monoxide

Q.

At a given place the barometric height falls suddenly and air is dry. The weather forecast can be

1. dust storm

2. rain storm

3. gentle breeze

4. mild drizzle

Q. Which of the following is an example of rapid combustion?

1. Burning of wood
2. Burning of LPG
3. Burning of coal
4. Burning of a candle

Q. A spoon was kept in contact with ice cubes for some time. Later, the same spoon was held over the flame of a small candle. The figure shows the observation. What do you infer from the given figure ?

1. Spoon is an inflammable substance.
2. Burning of candle is a spontaneous process.
3. $C{O}_2$ is a product of combustion
4. Water vapour is a product of combustion

Q. Which of the following do not form oxides easily?

1. Platinum
2. Aluminium
3. Sodium
4. Silver

Q. Wrap a thin paper strip tightly around an iron rod. Try to burn the paper with candle while rotating the iron rod continuously. Does it burn ?

Q. What will be the product formed when hydrogen burns in air?