8th Grade > Chemistry
COMBUSTION AND FLAME MCQs
Total Questions : 56
| Page 5 of 6 pages
Answer: Option A. ->
True
:
A
:
A
If air is blown around coal, then air circulation increases the supply of oxygen gas which will help in the complete combustion of coal. Supply of sufficient amount of oxygen gas lets the coal burn completely.
Answer: Option A. ->
Explosion
:
A
When a cracker is ignited, a sudden reaction takes place with the evolution of heat, light and sound. A large amount of gas liberated during this reaction. Such a reaction is called explosion.
:
A
When a cracker is ignited, a sudden reaction takes place with the evolution of heat, light and sound. A large amount of gas liberated during this reaction. Such a reaction is called explosion.
Answer: Option A. ->
True
:
A
:
A
The calorific value of a fuel is expressed in a unit called kilojoule per kg (kJ/kg). Calorific value is the term that is used to measure the efficiency of a fuel.
Answer: Option B. ->
electrical fires
:
B
Water is a good fire extinguisher. But, water cannot be used to extinguish electrical fires. This is because water is a good conductor of electricity. It can cause electric shock and can harm the person who is trying to put it off.
:
B
Water is a good fire extinguisher. But, water cannot be used to extinguish electrical fires. This is because water is a good conductor of electricity. It can cause electric shock and can harm the person who is trying to put it off.
Answer: Option B. ->
Chemical
:
A, B, C, and D
The three essential things that are required for a substance to burn are heat, fuel and oxygen.
Here the heat is produced by friction between matchstick and box. Fuel is the chemical at the strip of matchstick and wood. Oxygen is available in the atmosphere.
:
A, B, C, and D
The three essential things that are required for a substance to burn are heat, fuel and oxygen.
Here the heat is produced by friction between matchstick and box. Fuel is the chemical at the strip of matchstick and wood. Oxygen is available in the atmosphere.
Answer: Option B. ->
Spontaneous combustion
:
B
The type of combustion in which a material suddenly bursts into flames, without any external heat supply is called spontaneous combustion. For example, substances like phosphorus and sodium burn when kept open at room temperature.
:
B
The type of combustion in which a material suddenly bursts into flames, without any external heat supply is called spontaneous combustion. For example, substances like phosphorus and sodium burn when kept open at room temperature.
Answer: Option B. ->
Fuel produces energy to be used for work.
:
A, B, and C
:
A, B, and C
Fuel is defined as a substance that undergoes reaction with oxygen and produces energy. The process is called as combustion. The fuel can be liquid (kerosene), gas (methane) or solid (coal). The meaning of inflammable is that the substance has the ability to catch fire easily. Not all fuels are inflammable. Wood is one such example.
Answer: Option B. ->
Phosphorus
:
B
When a matchstick strikes on striking surface of a matchbox, the heat of the friction causes a reaction between the potassium chlorate in the match head and phosphorus in the striking surface.
:
B
When a matchstick strikes on striking surface of a matchbox, the heat of the friction causes a reaction between the potassium chlorate in the match head and phosphorus in the striking surface.
Answer: Option B. ->
Nitrogen
:
B
:
B
A fire triangle is a simple model for understanding the necessary ingredients for production of fire. The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and oxygen. Nitrogen gas does not support combustion. The image below shows a fire triangle.
Answer: Option A. ->
Nitrogen dioxide
:
A and B
Motor vehicles and the industries located in and around Agra releases sulphur dioxide and nitrogen dioxide into the atmosphere. These gases dissolve in rain water and form acids like sulphuric acid and nitric acid. These acids fall to the ground in form of rain and this rain is called acid rain.
:
A and B
Motor vehicles and the industries located in and around Agra releases sulphur dioxide and nitrogen dioxide into the atmosphere. These gases dissolve in rain water and form acids like sulphuric acid and nitric acid. These acids fall to the ground in form of rain and this rain is called acid rain.
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