Combustion And Flame

Combustion is a chemical process where a substance reacts with oxygen to produce heat and light. This is commonly known as burning.

Every combustible substance has a specific temperature at which it begins to burn. This is called its ignition temperature.

Combustible substances are those that catch fire and burn easily. Wood is a common example, while stone, iron, and water are non-combustible.

Non-combustible substances do not burn when exposed to fire. Glass is such a material, whereas paper, cloth, and kerosene will catch fire.

The head of a safety match contains antimony trisulphide and potassium chlorate, which help in ignition when struck against the rubbing surface.

The rubbing surface on a matchbox has red phosphorus and glass powder. The friction generates heat, converting red phosphorus to white phosphorus, which ignites the match head.

Air (or oxygen) is the supporter of combustion. Without it, no combustion can take place.

Rapid combustion is a process in which a substance burns quickly to produce heat and light. LPG burning in a stove is a perfect example.

Spontaneous combustion occurs when a substance catches fire on its own due to internal chemical reactions. Coal in coal mines sometimes undergoes this.

An explosion involves a sudden and violent release of energy, like when a firecracker bursts or a gas leak ignites.

For combustion to occur, all three elements—fuel, oxygen, and heat to reach the ignition temperature—must be present together.

Water absorbs heat, lowering the temperature below the ignition point, and also forms a layer of steam that cuts off oxygen supply.

Water conducts electricity and can cause electrocution in electrical fires. For oil fires, water can spread the oil, making the fire worse.

Carbon dioxide does not conduct electricity and cuts off oxygen supply, making it ideal for electrical fires. Sand also smothers the fire.

The outermost zone is the hottest and has the most oxygen, allowing complete combustion to occur. It appears blue and is non-luminous.

In the middle zone, incomplete combustion produces tiny carbon particles that get heated and emit yellow light, making the flame luminous.

The innermost zone is the coolest part of the flame. It contains unburnt wax vapors that have not yet started burning.

The outermost zone is the zone of complete combustion, which produces the most heat, making it the hottest part of the flame.

The water in the paper cup absorbs the heat from the flame, keeping the paper below its ignition temperature, so the paper does not burn.

Oxygen itself is not a fuel, but it is essential for combustion to take place. It is called the supporter of combustion.

Paper has a relatively low ignition temperature and catches fire easily compared to wood or coal. Iron is non-combustible.

Water is heavier than kerosene and will sink, causing the kerosene to float and spread the fire. Sand or a fire extinguisher smothers the fire by cutting off oxygen.

While wood and coal are used, kerosene and LPG (liquefied petroleum gas) are common liquid and gaseous fuels used for cooking.

Rusting is a slow oxidation process where iron reacts with oxygen over a long period to form iron oxide, releasing heat very slowly.

Digestion is a slow process of breaking down food, but it is not combustion. Combustion involves burning with oxygen to produce heat and light.

LPG stands for Liquefied Petroleum Gas, a mixture of propane and butane used as a fuel.

The ignition point, or ignition temperature, is the minimum temperature required for a substance to start burning.

The middle luminous zone has a limited supply of oxygen, leading to incomplete combustion of wax vapors.

The outermost zone is blue in color because it is the hottest part where complete combustion occurs.

Inflammable substances, such as petrol, LPG, and alcohol, have very low ignition temperatures and catch fire easily.

Before using any extinguisher, it is crucial to disconnect the electricity supply to prevent electrocution and further damage.

Friction between the match head and the rubbing surface generates enough heat to ignite the chemical mixture.

Petrol, kerosene, and diesel are liquid fuels, while natural gas is a gaseous fuel.

Carbon dioxide is non-combustible and does not support combustion. This is why it is used in fire extinguishers to smother fires.

The ignition temperature of a matchstick is above room temperature, so it requires friction to generate the necessary heat to ignite.

All three conditions—fuel, oxygen, and heat—are necessary for fire. Removing any one will extinguish the fire.

In rural areas, dried wood and cow dung cakes are commonly used as fuel for cooking and heating due to their availability.

Sand acts as a barrier between the burning material and the oxygen in the air, smothering the fire.

Inflammable substances, like petrol and alcohol, are dangerous because they ignite very easily.

Ignition temperature is the specific minimum temperature required for a particular fuel to start combustion.

The innermost dark zone contains unburnt wax vapors that have not yet undergone combustion.

LPG burns more efficiently, producing more heat per unit mass, and does not release smoke, making it cleaner than wood.

Asbestos is a fire-resistant material that does not burn, making it non-combustible.

Magnesium ribbon burns rapidly in air to produce a bright white light and heat, which is a form of rapid combustion.

Since petrol floats on water, pouring water only spreads the burning petrol over a larger area.

Oxygen is the gas that supports combustion. It is colorless and odorless and makes up about 21% of the air.

The burning candle uses up the available oxygen within the enclosed space of the chimney, and once the oxygen is depleted, the flame goes out.

Proper ventilation prevents the accumulation of gas in case of a leak, reducing the risk of fire or explosion.

Coal dust can undergo spontaneous combustion when it reacts with oxygen in the air, generating enough heat to catch fire without an external source.

Water has a high heat capacity; it absorbs heat, cooling the wood below its ignition point. It also turns into steam, which displaces oxygen around the fire.