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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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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Combustion and oxidation

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 ...
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Figuring out the theoretical mass of reactants

I'm working on my chemistry lab report. The initial instructions were to test the hypothesis that the mass of products of a reaction will equal the mass of the reactants. Basically we where given a ...
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Air contains 20 % O2 by volume. How many cm³ of air will be required for oxidation of 100 cm³ of acetylene?

Air contains 20 % $\ce{O2}$ by volume. How many cm³ of air will be required for oxidation of 100 cm³ of acetylene? (a) 1064 cm³ (b) 212.8 cm³ (c) 500 cm³ (d) 1250 cm³ Answer: (d) My solution: ...
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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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1answer
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How to calculate the amount of water produced by the incomplete combustion of propane?

I was wondering if someone could walk me through how to do the following two questions? The complete combustion of pentane has a enthalpy change of $-3509~\mathrm{mol^{-1}}$. Write an equation ...
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Can natural gas appliances run on Hydrogen?

Can natural gas appliances run on Hydrogen? If so, does the appliance have to be modified and how significant of a modification would it need? Thanks
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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 ...
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Why is the maximum adiabatic temperature found for an equivalence ratio a bit higher than 1?

Why does the peak adiabatic temperature usually happen for an equivalence ratio a bit higher than 1? I think it had something to do with the probability of each fuel molecule finding a corresponding ...
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1answer
32 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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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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1answer
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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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Why are methanol flames less visible than other flames?

The combustion of methanol tends to generate flames that are less visible than the flames generated by the combustion of other substances? My guess is that methanol burns quickly as it has a ...
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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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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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Can you melt wood?

We talked about it in our chemistry class but we couldn't get to a conclusion, any help?
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Ventilating combustion byproducts in water heaters

I'm designing a system which will heat up water by burning natural gas which is commonly available. I would like to have a slow flame because water will need to reach $\mathrm{70^\circ C}$ and stay ...
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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
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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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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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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
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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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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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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
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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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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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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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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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1answer
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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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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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What is the mechanism of alkane combustion?

I understand that combustion of hydrocarbons (such as alkanes) produces energy by breaking bonds: $$\ce{C_nH_{2n} + $\frac{3n}{2}$ O2 -> nCO2 + n H2O}$$ And I can find dozens of explanations of ...
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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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rate of combustion of alcohols and hydrocarbons in relation to the number of carbons in the chain

I understand that the heat released when burning alcohols is greater as long as the number of carbons in the alcohol chain is increased (i.e the enthalpy of butanol is greater than propanol > ...
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1answer
221 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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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
522 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
62 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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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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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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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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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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Determining stoichiometry of an unsaturated hydrocarbon via combustion

$60\ \mathrm{cm^3}$ of oxygen was added to $10\ \mathrm{cm^3}$ of a gaseous unsaturated hydrocarbon. After explosion and cooling to room temperature, the residual gases occupied $45\ \mathrm{cm^3}$. ...
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Can old matches combust spontaneously?

I came upon this box of matches, it's probably from a little before 1900 and has significance for my family history, and I would like to add it to my "box o' historical items" but I'm concerned about ...
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How is octane rating defined for negative values and those over 100?

Based on my reading, the octane rating for a given fuel is calculated by finding the compression ratio at which it knocks and finding a mixture of $X\%$ isooctane and $(100 - X)\%$ n-heptane which ...
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370 views

Is reduction of copper oxide a combustion reaction?

Is the following reaction a combustion reaction or just a single displacement? Could be both? $$\ce{H2 + CuO -> Cu + H2O}$$ A friend of mine claims it is a combustion reaction because it is ...

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