[Physics] Fire: Why is Carbon combustible and Why is Oxygen needed

combustion

This question is about the requisites of fire and combustion. My physics learning is only high school level.

In a nutshell, why are certain elements more susceptible to combustion while others are not, from a quantum level?

In other words, do the strong, weak, electromagnetic, and gravitational forces have something to do with the propensity of atoms to combust or to release light and heat energy when heat is introduced to them? If the causal force of combustion cannot be traced to those four forces singly, is there a name or terminology for phenomenon that leads to it?

The minute physics video shows the causes of the effect of fire as "atomic transitions" and "thermal radiation". It does not explain the causes of those causes or why carbon atoms get excited and release energy in the first place or why oxygen has to be there to create those transitions and radiation.

I hope by knowing the cause of the cause, then it will be easier to extend it forward to explain why aluminum or silicon atoms don't get as excited by heat under nitrogen to create fire in the same way carbon does under oxygen, for example.

Best Answer

Whether an element will be combustible or not, depends on whether its total energy after bonding with Oxygen increases or decreases. If enegry decreases, then its combustible buy if it's increases then the element is not combustible. Carbon atom has four electrons in its outer shell. It's energy decreases if it acquires four more electrons in the shell. So it bonds with Oxygen to achieve a lower energy state by releasing energy, which process is called Combustion.

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