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Questions tagged [combustion]

For questions about the combustion of an organic molecule or inorganic substance. Do not use this tag if your question is about the [stoichiometry] of a combustion reaction, or for the calculations of [thermodynamics] functions (like enthalpy change).

It is an exothermic process by which a substance is oxidized (by an oxidizing agent such as oxygen) to release a large amount of energy in the form of heat and often light.

Combustion is a reaction with complicated radical chain mechanisms, depending on substrates - combustible substance and oxidiser.

Combustible materials include most of the organic compounds (for example petrol and ethanol) and many inorganic ones (like ammonia and boranes), as also many elementary substances, like carbon, sulfur or more reactive metals.

Oxygen is most popular oxidizer for combustion, but also chlorine, fluorine, and compounds of these elements can be used.

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What is going on in and below a yellow or blue gas flame?

Unsure if this is more chemistry or physics, but here goes... Consider a Bunsen burner and the flame it produces when the air inlets are closed vs open. According to the description on the linked Wikipedia page, combustion is incomplete when the air…
Anthony X
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Why is O2 the supporter of combustion?

It's there in every high-school textbook: $\ce{O2}$ is the supporter of combustion. Without $\ce{O2}$ combustion cannot take place. Why? And why only $\ce{O2}$? Why not some other element? And, what happens when a combustible gas burns in air? Say…
Gerard
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What is the difference between ignition temperature and flash point?

I am trying to clarify this for Class 8 Science. Their textbook says "It is the lowest temperature at which a substance catches fire". However, it does not clarify whether it is on its own or due to an external source. I read through various…
Arpita Karkare
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In a Koppers-Totzek reactor, why do I get CO and H₂ instead of CO₂ and H₂O?

A Koppers-Totzek reactor (there seems to be only a German Wikipedia page) is an entrained flow gasifier that blows coal dust, oxygen and water (as steam, of course) into a burning chamber where the coal burns at about 1600 °C. The output contains…
Hanno Fietz
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Combustion in liquid state

Normally, we think of combustion as occurring only in the gas phase. I think I understand the main reason for this - in the gas phase it's very hard for a bimolecular reaction to produce a single product, which makes it more likely for radical chain…
N. Virgo
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Why doesn't the carbon dioxide produced by a fire put out said fire?

Carbon dioxide ($\ce{CO2}$) is used in some fire extinguishers to put out fire, but a combustion reaction itself produces $\ce{CO2}$. Why do we get fire then? $$\ce{CH4 + O2 -> CO2 + H2O}$$ Why doesn't this $\ce{CO2}$ put out the fire?
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Why does old gasoline seem to have more "kick"?

From my personal experience, old gasoline (leftover in a container from the previous year) has more "kick" (power) when I actually use it. Higher idle RPM, higher throttle sensitivity. It says here that it's not the gasoline itself that burns, but…
user54392
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Is oxygen necessary for burning?

Is oxygen really necessary for burning things? What if there was no oxygen around? Would there still be a way to burn things?
Prakhar
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Are there substances that cannot undergo combustion?

Are there substances that cannot undergo combustion? If so, what are they?
startanew
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Phenomenon where fumes can relight an extinguished flame

I lit a mosquito coil and used it to melt down small down candle wax which had fallen on the floor. The coil then produced some dense fumes. I directed the fumes to the flame of a candle. As soon the fumes reached the candle, my coil caught fire…
sin
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What causes incomplete combustion?

During the combustion of hydrocarbons, there is a difference between the amounts of carbon or hydrogen that results in incomplete or complete combustion of the material. My question is, besides from an insufficient amount of oxygen, what can cause…
phi2k
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Do all flames require the same minimum concentration of oxygen to sustain themsleves?

Assume you have burned some substance A in an airtight container until the fire goes out due to insufficient oxygen. You then place some burning substance B in the container through an airlock. Are there substances A and B such that the substance B…
Steve B
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Maximum pressure that can be produced by a combustion reaction

Multiple-chamber artillery can launch a projectile with energies much higher than single-chamber guns. I'm interested in setting a fundamental upper bound on the energy that a chamber (of a known volume) can impart to a projectile. This would, for…
AlanSE
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Why don't the products of combustion stop combustion?

We know that combustion of fuels give water and carbon dioxide (during combustion of hydrocarbon) as a byproduct, but why don't these byproducts stop combustion?
ashi
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Is it possible to combust a plasma?

In what we usually consider combustion your fuel and oxidizer are always neutral, but is it possible to have a similar "explosive" combustion process where both the fuel and oxidizer have been singly ionized? If so what might some potential fuels…
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