Petrol is primarily characterised by its octane number which defines its ability to burn efficiently and produce more energy per unit. A low octane petrol particle blast inside the engine instead of burning from spark this is called knocking as it produces knocking sound in the engine, to counter this an anti-knocking agent is added to petrol. Earlier Lead was used as an anti-knocking agent but it is highly toxic ,also the researchers who experimented lead with petrol died unnatural death. In later stages when effects of lead toxicity started showing up lead was replaced by benzene compounds as anti-knocking agents this is know as Unleaded petrol. Benzene is carcinogenic and started showing its ill effects after few years especially in densely populated cities. Govts have reduced the concentration of benzene in petrol thereafter and emphasised on implementation of Euro iv standards.
Only gas or vapor can be superheated. Use water as an example. Water at sea level boils at 212 degrees F. When heated to 212 degrees F, the molecules that make up water are moving at a high enough speed that they overcome the air pressure above the water. And for supercooled only liquids or solids can be supercooled for example Liquid water at sea level has a saturation (boiling) temperature of 212 degrees F. If we were to add heat to the saturated water, it would first boil away with no change in temperature (remember latent heat?) and then become superheated if still more heat were added to the vapor (steam) after it had all turned to a vapor.
Answer:
A solid has a definite volume and shape, a liquid has a definite volume but no definite shape, and there is no definite volume or shape of a gas. Usually, the transition from solid to liquid does not change a substance's volume substantially.
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The ancient Greeks believed that fire was one the four basic elements that composed all things in the universe. In the mythology of virtually every culture, fire is a sacred substance that gives life or power. Fire is not, in fact, a substance. When you gaze at the leaping flames of a campfire, you’re observing not an object, but a process – a chemical reaction. It’s the same chemical reaction that occurs when a cut apple left on the counter turns brown, when silver tarnishes or when an iron nail rusts.
That process is oxidation: combining oxygen with another substance. The defining difference between a fire and your half-eaten apple is speed: fire is an oxidation process that happens very fast, so that light, heat and sound are released — often with enough force and majesty to justify the ancients’ reverence.The sudden release of energy causes temperatures to rise, sometimes by thousands of degrees. And it also results in smoke, the toxic waste of fire’s leftovers.
The fire triangle and the fire tetrahedron
Fire TetrahedronThe fire triangle identifies the three needed components of fire:
fuel (something that will burn)
heat (enough to make the fuel burn)
and air (oxygen)
Explanation: i hope this helps sry its long
B is the answer..............
