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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3answers
149 views

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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1answer
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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 ...
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3answers
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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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3answers
103 views

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, DMT. But ...
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36 views

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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0answers
32 views

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}...
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2answers
180 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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1answer
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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 ...
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2answers
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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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0answers
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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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1answer
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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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2answers
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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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1answer
35 views

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 ...
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2answers
74 views

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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0answers
35 views

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 ...
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2answers
155 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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0answers
30 views

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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38 views

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 ...
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1answer
38 views

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 ...
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1answer
641 views

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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0answers
90 views

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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0answers
39 views

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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1answer
56 views

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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118 views

Why do nitrogen-containing organic compounds give N2 as the combustion product?

My teacher gave the explanation stating that consider that first the nitrogen in lower state is oxidised to $\ce{N2}$ and then the further oxidation would stop as the $\ce{N-N}$ bond energy of $\ce{N2}...
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1answer
161 views

Why does charcoal not produce smoke when heated?

As I understand; the reason we have smoke in a fire is because the heat causes wood (or whatever material is burning) to dis-integrate, the disintegrated components react with oxygen to create more ...
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1answer
36 views

Finding Gibbs energy at different temperatures just given Gibbs energy at one temperature

How would it be found the Gibbs energy at a certain temperature, if they just give you another Gibbs energy at a temperature? For example: Given $\Delta G = -230 Kcal/mol$ at $773K$ for the reaction $...
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1answer
36 views

Is incineration of a solid fuel complete or incomplete?

If I have some solid material like biomass and incinerate it at 1000 Celsius degrees for 15 minutes in an oxidized atmosphere within an incineration oven. As an output it gives me ash. Is the ...
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26 views

Verify heat produced by flame using enthalpy of fomation

I'm simulating using a CFD solver a pure oxygen/methane flame. However, I doubt that the combustion model does not produce enough heat. The heat from reaction is defined by $S_h=-\sum_{j} \frac{h_j^0}{...
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1answer
135 views

What is change in internal energy of a system in which combustion occurs at constant temperature?

We got a question in a test, in which we were asked which system has zero change in internal energy and it had an option which was combustion of methane at constant temperature. I imagined this to be ...
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0answers
128 views

What causes little spikes in a flame? [closed]

I have a lighter at home which everytime I use it, generates little spikes (see picture below) which eventually disappear. The Spikes are not an effect generated by the camera. I can confirm that ...
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5answers
738 views

Why do different substances containing saturated hydrocarbons burns with different flame?

LPG and Candle wax both contain saturated hydrocarbon, yet LPG gives a clean white flame but a candle gives yellow flame with lots of smoke. Why so? I have read some answers on web which says that it ...
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2answers
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Why doesn't NASA or SpaceX use ozone as an oxidizer for rocket fuels?

Presumably, it would be expensive to use ozone ($\ce{O3}$) as an oxidizer instead of $\ce{O2}$, but would the extra oomph be worth it? Does $\ce{O2}$ provide as much thrust/energy/heat as can be ...
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0answers
59 views

Why is gasoline consisting of heavily branched alkanes better fuel than gasoline consisting of more linear alkanes? [duplicate]

As far as I know, the reason isooctane is better than octane in gasoline engines is because the octane is more prone to ignition by pressure. This makes it ignite when it is not supposed to, which ...
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1answer
76 views

Combustion of NaCl(aq) when testing conductivity

In a experiment that dealt with electric conduction of many concentrated solutions, NaCl(s) created an unknown, to me, substance after adding a drop or two of water. Furthermore, it isn't the reaction ...
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0answers
42 views

Where can I find the released combustion energy in NASA CEA rocket problem?

I am using NASA CEA program for a study project. I have read the CEA Nasa user's manual over and over, yet I haven't found an answer to my question which is : where can I found in the output of NASA ...
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1answer
146 views

Combustion of methane and ethane

I'm having trouble with the following problem: A gas fuel of Methane ($\ce{CH4}$) and Ethane ($\ce{C2H6}$) is burned with atmospheric air, and the volumetric analysis of the products of combustion ...
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1answer
42 views

Viability of reduction of oil paint binder and solvent flammability upon disposal via addition of water

As an artist, when disposing of a paper towel or cotton rag containing oil paint, turpentine, odorless turpentine substitute or mineral spirits at the end of a painting session, I generally pour water ...
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1answer
393 views

How or Why does diesel/kerosene have a much higher 'flash point' but lower auto/self-ignition point than gasoline/petrol?

This is a very common question, but I have yet to find a good theoretical answer to both questions (diesel has higher flash point BUT lower spontaneous ignition temp.)
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2answers
156 views

Controlled burn with colored flames (Gender Reveal) [closed]

Is there a single solvent that can dissolve chemicals/elements that when burned, will produce the color of its respective chemical/element? If so, what chemical/element can be dissolved in this ...
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2answers
726 views

Calculating the amount of oxygen in a glass using candle burning time

I would like to calculate the amount of oxygen or concentration of oxygen in a glass or conical flask using candle burning time. I am thinking of a simple way to calculate this based on the fact that ...
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1answer
69 views

What is the opposite of a catalyst and examples? [duplicate]

I remember a while ago I heard of something that slowed reactions and was effectively the opposite of a catalyst. What is this called? Also would appreciate examples and an explanation of their uses ...
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2answers
867 views

Could blue flames arise within the hull of a burning ship?

In Joseph Conrad's Youth: A Narrative, set in 1876, a 400-ton barque ship, the Judea, is sent to Java Head to transport 600 tons of coal. Although various delays occur during its journey, the coal it ...
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1answer
333 views

What is the significance of heating value?

Say I burned for example methane and propane to boil some water. Methane has the heat of combustion of $\pu{890kJ/mol}$ and propane has the heat of combustion of $\pu{2200kJ/mol}$ What does the ...
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2answers
196 views

How much does oxygen enrichment improve some combustion engines?

This question is about how much the combustion efficiency increases with oxygen enrichment in modern combustion engine designs. A desirable way to answer is to give the fuel efficiency dependency on ...
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5answers
2k views

On heating in the Earth's atmosphere, can magnesium react with nitrogen to form magnesium nitride?

This question is derived from a question asked in my school test. What happens when a magnesium ribbon is heated in air? My first response was the formation of magnesium oxide $(\ce{MgO})$ when ...
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0answers
27 views

How to get the right formulas for combustion (rocket chamber) or where to find them? [closed]

I am a space enthusiast and am intrigued mostly by rockets. I recently found a book HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES and have been fiddling around with rocket engine ...

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