Chapter-6 Combustion and Flame - Extra questions

Explanation:

Because it is a high-quality fuel and has some advantages, the use of CNG in automobiles has reduced pollution in our cities: 

a) It releases less carbon dioxide, carbon monoxide, sulfur dioxide, and nitrogen dioxide, all of which contribute significantly to acid rain and global warming. 

b) When it burns, there is no residue left behind. 

Explanation:

Because the green leaves contain some water, their ignition temperature rises, making it difficult to burn. Then again, dry leaves are waterless, so they burst into flames effectively (having low start temperature). 

Explanation:

Because CO2 is heavier than oxygen, it covers fires and stops the flow of air because of this. It lowers the burning substance's temperature, men over. In these ways, it assumes a huge part in controlling fire. 

Explanation:

Because it is the hottest and has a higher temperature, a goldsmith melts gold and silver in the non-luminous outermost zone of a flame.

Explanation:

Substances combustible: Combustible substances are things like paper and cloth that easily ignite. 

Substances that are not flammable: Non-combustible substances are those that do not easily ignite, such as iron and glass. 

Explanation:

Because it is not combustible and does not support combustion, carbon dioxide is used to put out fires. Additionally, it settles on the fire and is heavier than air. 

Explanation:

A fuel is a substance that produces heat and energy when burned. The fuels kerosene and gasoline are liquids.

Explanation:

Water is a conductor of electricity, so using it to put out a fire caused by an electric short circuit could cause an electric shock. 

Explanation:

Because they have different ignition temperatures, different substances catch fire at different temperatures. 

Explanation:

Spontaneous combustion, such as that of phosphorus, is a type of combustion in which a substance spontaneously bursts into flame.

Explanation:

When hydrogen and oxygen mix, it explodes and is difficult to handle. As a result, it does not serve as a fuel.

Explanation:

Due to its low ignition temperature, petrol easily vaporizes and ignites. As a result, using it in stoves is risky. 

Explanation:

With a flame, camphor vaporizes to the bottom, whereas charcoal does not. Camphor has a low ignition temperature. 

Explanation:

The temperature of burning wood drops below its ignition temperature when water is poured on it. This stops the spread of the fire. 

Explanation:

At times during the summer's extreme heat, dry grasses catch fire. After this fire reaches trees, the entire forest is on fire. 

Explanation:

● It is modest and effectively accessible. 

● During combustion, it produces no harmful gas. 

● It has a lot of calories. 

● It can be stored safely and easily. 

● Compressed Natural Gas, or C.N.G is utilized as a vehicle fuel. 

Explanation:

The dark zone is the innermost area. Wax vapors that are unbumt contain it. The yellow zone, which is the second zone, is where incomplete combustion occurs. The term for it is "luminous zone." 

Complete combustion takes place in the thin, blue-colored flame's outermost region. This is the area without light.

Explanation:

The foam-type fire extinguisher, which works by smothering the fire, is used at airports and gas stations. Turkey red oil is contained in the sodium bicarbonate in this fire extinguisher. When it is turned on, the foam-like carbon dioxide that is released as a result of the reaction between diluted sulphuric acid and sodium bicarbonate settles on the fire. 

Explanation:

● Carbon energizes discharge unbumt carbon particles and cause asthma. ● Carbon monoxide, a gas that is harmful, is produced when incomplete combustion occurs. 

● Global warming is caused by the emission of carbon dioxide from fuel combustion. ● Acid rain is bad for crops, buildings, and the soil because of the increased use of fuel. 

Explanation:

Wood is utilized in villages because it is inexpensive and readily available. Among its drawbacks are: 

● It makes a lot of smoke, which makes it hard to breathe. 

● Wood contains a few significant substances which are lost when it is singed, ● Slicing of trees prompts deforestation. 

Explanation:

When a person's clothes catch fire, they are covered with a blanket to put out the flames. This is because when the person is covered with a blanket, the air supply to the clothes stops and the fire stops. 

Explanation:

Explosive combustion is a rapid combustion reaction that results in a significant amount of heat, light, and sound. Rapidly, a large quantity of gases are released. The loud sound is caused by these gases' rapid expansion. Example: fireworks on days of festivals. A sudden change occurs when a cracker is ignited, resulting in the development of heat, light, and sound.

Explanation:

The safety match's head now only contains potassium chlorate and antimony trisulfide. The scouring surface has powdered glass and a little red phosphorus (which is considerably less perilous). Some of the red phosphorus is transformed into white phosphorus when the match strikes the rubbing surface. This immediately reacts with the potassium chlorate in the matchstick head to generate sufficient heat to ignite the antimony trisulfide and initiate combustion. 

Explanation:

● For quite a long time, wood was utilized as homegrown and modern fuel. However, coal and other fuels like LPG now take its place. 

● Because LPG has a much higher calorific value than wood, it burns much hotter than wood of the same mass. 

● While burning wood produces a lot of smoke that is extremely harmful to humans, LPG burns without producing any smoke. 

● While wood produces a lot of ash when burned, LPG completely burns without leaving behind any solid residue. As a result, LPG is a cleaner fuel than wood. 

● While cutting down trees for wood results in deforestation, which is extremely harmful to the environment, LPG does not pose a threat to the environment. 

Explanation:

Place a lit candle on the table. Place a glass chimney over the candle and set it on a few wooden blocks so that air can get in. In case (a), when air can enter the chimney from below, we will observe that the candle burns freely. The chimney should now be placed on the table and the blocks removed. 

Now, we will observe that in case (b), the flame flickers and emits smoke when air does not enter the chimney from below. Finally, cover the chimney with a glass plate. In this scenario, (c), the absence of air causes the flame to finally go out.

This observation demonstrates that combustion (or burning) cannot occur without air.