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).

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How stable are paper book matches?

I have few hundred paper book match books that I collected about 25 to 45 years ago when many businesses had them custom printed. They are from around the world although mostly US. They are in an open ...
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Where does the heat energy come from when you burn hydrogen and oxygen together? [duplicate]

I notice when you burn hydrogen and oxygen together, it forms water, 2H2 + O2 --> 2H2O. Further I notice, atoms does not reduce/destroy in this equation but ...
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When hydrogen and oxygen reacts, what defines if it will turn into hydrogen peroxide or water?

If you have a jar with oxygen and hydrogen inside, I'm interested in knowing what variables are most important to ensure that the mixture will become water (if that was the goal) or hydrogen peroxide, ...
3 votes
1 answer
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Are solid fuels with calorific values >= 10,000 kcal/kg (42 MJ/kg) physically possible?

I have seen laboratory documentation from a reputable lab in southeast Asia that a company has achieved a solid fuel product made from landfill material with a high heating calorific value ($CV$) of ...
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Is there an intuitive answer why burning is very exothermic? [closed]

Water and carbon dioxide are much lower in energy than hydrocarbon and oxygen. Is there an intuitive answer for this? Is this because atom arrangements that have more polar bonds tend to be lower in ...
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1 answer
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What chemicals can remove or greatly reduce the smell of burning diesel fuel?

I am not a chemist myself but I am trying to solve a practical problem I am experiencing. I have a nicely working diesel stove but it produces some smell. I've read that adding urea to the exhaust may ...
3 votes
1 answer
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How can combusted methane from landfill samples be quantified?

Background: For my studies I'm wanting and attempting to make a landfill greenhouse gas emissions (GHG) model that predicts the amount of greenhouse gas equivalent emissions ($GHG_\mathrm{eq}$ [tonnes/...
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6 votes
3 answers
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Does stoichiometric gas mixture produce the highest explosion pressure (or energy) compared with other explosive limit mixture?

I understand that a stoichiometric mixture contains a balanced mixture of air and fuel and both fuel and air are completed consumed. For example, the ideal stoichiometric mixture for propane is ...
-2 votes
1 answer
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What's the stoichiometric ratio of Kerosene to a mixture of 50% water and 50% hydrogen peroxide [closed]

So I'm wanting to do some testing with combustion of certain liquids, and I'd like to know what the right ratio is for these liquids. What I'm going to be using is regular kerosene (NOT RP-1) and 50% ...
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6 votes
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Equilibrium constant vs Reaction rate constant

For a reaction, e.g., $$a X + b Y → c Z$$ Its reaction rate constant is $${\displaystyle r=k_f(T)[\mathrm {X} ]^{m}[\mathrm {Y} ]^{n}}$$ where the exponents m and n are called partial orders of ...
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What happened after fire finished burning? [closed]

After fire finished burning, did it merge with the atmosphere and becoming water vapors, oxygen and nitrogen, or did it simply disappear into nothing?
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Understanding Hydrocarbon Combustion [duplicate]

First ... I know almost nothing about chemistry. So, for the past week or so, I've kind of been fascinated with this whole combustion thing (not in an evil way, of course). So, I've been reading, and ...
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1 answer
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What compounds smell like burning rubber or tar?

Background: A couple of friends of mine live next door to each other in a 10-year old block of flats in London, UK. They say that in the early hours of the morning, a toxic smell appears in their ...
1 vote
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Aproximation of H2 combusion limits

I'm looking for a relatively simple approximation for combustibility limits of H2/O2/N2 gas mixtures over temperature/pressure. (It doesn't need to be conservative.) I've found a fair bit of data for ...
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Understanding uni- and termolecular reactions in combustion kinetics

I'm trying to understand and incorporate 9-species 19-reaction H2/O2 combustion mechanism into my numerical solver. The reaction mechanism in question is O'Conaire. It seems that the paper is in some ...
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Could perchlorate salts allow for underwater combustion?

So apparently perchlorate salts can act as oxidizers for combustion (basically they can replace oxygen in the fire triangle, at least I think), and the reason why you can't have a fire underwater is ...
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Are carbon nanotubes and graphene very flammable?

The reason I ask is because carbon is quite flammable in virtually every shape we encounter in nature. Even diamonds burn as a matter of fact. And after I just saw some steel wool burn easily, I ...
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2 answers
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Is it possible to modify how energy is released in the combustion of a fuel like methane? [closed]

From what I understand (please correct me if I'm wrong), combustion is an exothermic oxidation reaction where, for example, a fuel like methane is combined with oxygen, i.e. CH4 + 2O2 → CO2 + 2H2O. My ...
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Why would tellurium + sodium hydroxide have worked as a good anti-knock gasoline additive (if it wasn't so smelly)?

The April 22, 2022 Veritasium video The Man Who Accidentally Killed The Most People In History mentions several aspects of the historical use of tetra-ethyl lead in gasoline, the resulting widespread ...
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1 answer
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What is the most stable cycloalkene? [closed]

I'm looking specifically at cyclopentene and cyclohexene. Supposedly, greater instability would lead to a more exothermic enthalpy of combustion. However, based on my data, cyclopentene is more ...
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2 votes
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Origin of oxygen content among the products of burned carbohydrates

For simplicity, I am only considering complete combustion. I am ignoring variants such as deoxyribose, just pure carbohydrates. Balancing the equation is easy due to the definition of carbohydrate: we ...
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How much heat is exchanged by this system?

I am having trouble with the following question: We allow $\pu{18 g}$ of oxygen to react with $\pu{23 g}$ of ethane. The reaction is shown below. Since the heat of combustion of ethane is $\pu{-1560 ...
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How holes in cooking burner help it to perform complete combution but candle thread can't by providing sufficient oxygen supply?

Recently I was introduced to organic chemistry for the first time. In the section of complete and incomplete combustion of carbon compounds, they provide example of two different objects, namely a ...
2 votes
3 answers
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Do molecules containing enough oxygen to burn themselves exist?

Is there a molecule with enough oxygen in it (for example, something like $\ce{HCOOOH}$) such that it can undergo complete combustion without requiring any additional oxygen? For example the above ...
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Is the activation energy higher in incomplete combustion or in complete combustion?

I am looking into high school level chemistry where it is asked if the incomplete combustion of methane into carbon monoxide has a higher activation energy then its complete combustion. My reasoning ...
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1 answer
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Where does the energy from combustion come from?

I am aware that combustion reactions are exothermic. The energy stored in the chemical bonds of the products is less than the energy stored in the chemical bonds of the reactants. The difference in ...
18 votes
3 answers
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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 ...
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Does smoking drugs degrade them?

Why doesn't smoking a drug degrade or destroy it? A wide variety of psychoactive compounds ("drugs") are commonly consumed via smoking – e.g., nicotine, THC, amphetamines, cocaine, and DMT. ...
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Why do hydrocarbons give out a blue flame on complete combustion? [duplicate]

In complete combustion of hydrocarbons the colour of the flame is blue. But what is the reason behind the flame being blue and not green or black or any other colour? Edit: I've searched the web for ...
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Why is the the temperature change due to the combustion of paraffin wax so high (10000 Kelvin)? [closed]

I'm trying to work out the temperature change (I got something like 10k Kelvin,hotter than the Sun's core...) caused by the combustion of paraffin wax which has a molar enthalpy of combustion $E^{wax}...
1 vote
2 answers
455 views

Combustion analysis of hydrocarbon

Combustion analysis of a hydrocarbon produced 33.01 g CO2 and 4.84 g H2O. I was asked to find the empirical formula of the hydrocarbon. I used these molar mass values for my calculations: C - 12.0107 ...
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Looking for gas or liquid for story research

I am working on a story for adaptation into animation. Main lead is a chemist in a traditional fantasy setting. The chemist uses her own compound to battle using fire or explosions. I love the ...
6 votes
2 answers
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Why do alkenes (olefins) burn hotter than alkanes (paraffins), even though alkanes are denser and more hydrogen-rich?

Burning hydrogen releases more total energy than combusting carbon, and all alkanes are denser as well, so why are flame temperatures for alkene molecules higher than their equivalent alkanes? P.S.: ...
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What is the coolest known flame? [duplicate]

Inspired by this youtube demonstration by ChemicalForce, I'm prompted to ask what is the coldest possible flame. What the video seems to show is phosphorus vapour in an inert gas being blown into air. ...
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Balancing octane combustion reaction for internal combustion engine

I am trying to balance out the equation for combustion of octane in $120\,\%$ of excess air with products $\ce{CO2},$ $\ce{H2O},$ $\ce{N2},$ and $\ce{O2}$: $$\ce{C8H18 + 1.2$a$(O2 + 3.76 N2) -> $b$ ...
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1 answer
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Looking for a compound that when mixed with sugar will burn when a drop of water is added

Years ago, I watched a Johnny Carson episode where a guest on the show mixed a compound with ordinary table sugar and added a drop of water and the mixture burst into flames. I went and bought the ...
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2 answers
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Is a hydrocarbon necessary for combustion? [closed]

Oxygen, heat and fuel are essential for combustion. What counts as a fuel? Is a hydrocarbon essential for combustion? Is combustion, say, of magnesium really combustion? And what's the difference ...
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1 answer
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Which is more efficient way to generate energy using hydrogen: direct hydrogen combustion or through fuel cell? [closed]

Which is more efficient way to generate energy using hydrogen: direct hydrogen combustion or through fuel cell? Please explain so that even a primary school student can understand.
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Does release of nicotine from tobacco require combustion, or an open flame?

I am interested in the combustion argument Phillip Morris is making regarding its iqos product. They claim there's no combustion in their product but how do you take nicotine out of something without ...
1 vote
2 answers
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Combustion and oxidation [closed]

What is the difference between combusting and oxidizing? Oxidation of alcohols leads to formation of aldehydes and carboxylic acid whereas the combustion of alcohols leads to the formation of carbon ...
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Does incomplete combustion produce carbon dioxide at first? [duplicate]

I know that the incomplete combustion of a hydrocarbon produces $\ce{CO}$ or sometimes $\ce{C}$ if the amount of oxygen is very limited, but I was wondering if at first $\ce{CO2}$ is produced and only ...
3 votes
2 answers
294 views

Mechanism of combustion of hydrocarbons [duplicate]

While this question comes close, it doesn't quite answer my question. Adding heat to oxygen & a hydrocarbon breaks the atoms apart and they reform into carbon dioxide and water. I get that. I want ...
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How can flammable gas become non-flammable when mixed with another gas with comparable percentage?

For example, R-410a is a 50-50 mixture of R-32 and R-125. R-32 is flammable (class A2L) and R-410a is not flammable (class A1). Flammability of refrigerant is mainly a concern when it is leaked since ...
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Why does Red Phosphorus react so violently with an oxidizer like Potassium Chlorate?

In Armstrong's Mixture, mixing those two chemicals results in a friction sensitive explosive which produces a loud bang. According to wikipedia, it is made by adding a strong oxidizer to red ...
1 vote
1 answer
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Can oxidizing agents be used to increase the combustion efficiency of waste oil?

Waste oil is atomized and combined with air to produce a very high temperature flame capable of melting iron. I was wondering if it's possible to further increase its combustion efficiency by mixing ...
7 votes
1 answer
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Does all fire only emit light on its outermost shell?

This question is about light emission, which may overlap with physics, but I am most interested in combustion and types of flame (incandescence, petrochemical fuel flames, nuclear ractions). Consider ...
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What is the explanation of negative temperature coefficient in ignition delay of a fuel?

When studying the ignition delay of a fuel, some fuel have a negative temperature coefficient area (NTC) where an increase of initial temperature of the mixture air/fuel produces an increase of the ...
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What happens if you superheat timber in a zero oxygen environment? [duplicate]

I was thinking to myself, what would happen if you were to put a lump of wood in a zero oxygen environment and superheat it? It couldn’t burn because fire needs fuel, heat and oxygen however because ...
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What color would be produced by the burning of the listed chemicals of the projectile weapon the carcass?

The carcass was a projectile weapon developed by the French in the second half of the 17th Century. It was "named carcass because the circles which pass from one ring, or plate, to the other, ...
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Why constant volume combustion gives higher energy than constant pressure?

I have noticed when I have done some combustion equilibrium that enthalpy is higher when doing a constant volume combustion than pressure constant combustion. Why is it so ? What are the reasons ...
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