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/or light.

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combustion reactions are exothermic, so why are reactions of metals with oxygen endothermic? [on hold]

All textbooks or websites I have visited say that combustion reactions are exothermic, yet I know that when a metal reacts with oxygen and forms a metal oxide it is an endothermic reaction. Isn't this ...
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26 views

How do I balance the reaction equation for combusting 1mol of 70%Butane 30%Propane gas mix, with excess air?

I am trying to work out how much water will be produced from the combustion of 1 mole butane/propane gas mix with air for an engineering project.
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32 views

Is it possible to find fire outside the Earth?

Excuse me if the question is silly, I have very little knowledge of chemistry. We can find oxygen in many places in the universe, but all the combustibles we use to light fire seems to be organic: ...
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1answer
15 views

Can covalently bonded hydrocarbons be influenced by a magnetic field?

I am doing a University project on Magnetically Assisted Combustion and am curious to know more about how magnetic fields may or may not affect gases such as butane and propane. I think I am right ...
4
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1answer
57 views

Chemical equilibrium for simultaneous dissociation reactions

While calculating the adiabatic flame temperature for the following combustion reaction: $$\ce{\Phi\, C2H6 + $3.5$\,(O2 + $3.76$\,N2) -> $a$\,CO2 + $b$\,CO + $d$\,H2O + $e$\,H2 + $f$\,O2 + ...
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1answer
55 views

What is the enthalpy of combustion for ethene given the values of enthalpy of formation?

I have answered this question and got a value of $\mathrm {1409 \space kJ\ mol^{-1}}$ however, the answer sheet says $\mathrm{-1009}$. Using the equation: $$\ce{C2H4 + 3O2 -> 2CO2 + 2H2O}$$ I ...
2
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1answer
22 views

“Alkanes must be vaporised before they will burn” - what does this mean?

What does this sentence mean - I assumed that burning vaporised something? If something is vaporised, isn't that turning it into a gas? How can you burn a gas? This is a sentence in my AS Chemistry ...
2
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1answer
57 views

Can paper burn without oxygen or air?

i.e: If you put a paper inside an oven vacuum packed and go beyond 250ºC, will it burn? There's no oxidizer. If not, what will happen?
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13 views

What would be the products? [duplicate]

So today in chemistry I did a lab by reacting calcium carbide with water to form acetylene gas. I brought a burning splint to the mouth of every test tube and waited until a reaction was complete. One ...
6
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2answers
38 views

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 ...
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1answer
37 views

Question regarding molar heat of combustion

Hi, I am able to do this question without the "80% of the heat released was absorbed by the water" part, and ended up getting 892.2g How, does "80% of the heat released was absorbed by the water" ...
4
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1answer
61 views

Equivalence ratio explained

To let you know where I'm coming from: I haven't studied chemistry since high school. I am now studying something else, but I have a dataset coming from your field and I would like some help in ...
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24 views

How do things heat one another? [duplicate]

For example, how does a gas stove heat a metal pot? A combustion reaction between the gas and the air takes place, and this releases energy due to new chemical bonds being formed. Do the atoms in ...
3
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2answers
47 views

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 ...
2
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1answer
55 views

Creation and Combustion of Nitrocellulose

I am intending to demonstrate the formation and combustion of nitrocellulose with my high school students, however I am concerned about the potential products of the combustion equation. I have been ...
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1answer
25 views

Calculating moles of Hydrogen gas in multiple gas container

If there was a 500 mL container filled with oxygen and hydrogen so it burns completely (2H:1O), how many moles of hydrogen gas would there be if there if pressure is 101.3 kPa and the temperature is ...
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1answer
62 views

Why do internal combustion engines only burn to carbon monoxide, not dioxide?

Why don't diesel and regular car engines burn all the way to $\ce{CO2}$?
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1answer
61 views

Can we do combustion caused by limited supply of air in a lab? How?

For example Ethyne in combustion by limited supply of air $$ \ce{ 2C2H2 + 3O2 ->[\Delta] 2CO2 + 2H2O + 2C } $$ vs. $$ \ce{ 2C2H2 + 5O2 -> 4CO2 + 2H2O + Energy } $$ What are the ...
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1answer
63 views

Can there be active THC be trapped in the evaporator?

When you smoke a marijuana blunt will there be any active THC residue trapped inside the blunt after the flame goes out? Wouldn't some of it get stuck inside because the blunt is not a hollow tube? If ...
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2answers
115 views

How to determine the empirical formula for terephthalic acid from its combustion products?

Terephthalic acid is an important chemical used in the manufacture of polyesters and plasticisers. It contains only $\ce{C}$, $\ce{H}$, and $\ce{O}$. In one experiment, $0.4953~\mathrm{g}$ of the ...
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1answer
103 views

How much oxygen is necessary for the combustion of ethane? [closed]

Dicarbon hexahydride plus oxygen creates $\ce{CO2}$ and $\ce{H2O}$. How many oxygen atoms are needed to make $128.4~\mathrm{g}$ of $\ce{CO2}$?
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1answer
24 views

Which enthalpy changes map to the alternative reaction routes under Hess' law?

I am searching for a method that would always allow me to determine which enthalpy changes map to which reaction routes using Hess' law. For example this exam question: And then I end up doing ...
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1answer
38 views

Why does a smaller amount of propanol burn slower than a much larger amount?

Why does $30~\mathrm{mL}$ of $\ce{C3H7OH}$ burn in 1 second (inside a water jug) compared to a sixth of the amount: $5~\mathrm{mL}$ of $\ce{C3H7OH}$ (on a plate) burn in 180 seconds? Why does the ...
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49 views

Auto ignition of tert-butyl mercaptan mixed with mineral oil

I am designing an experiment that involves immersing pieces of pipe lining in a mixture of tert butyl mercaptan (2%) and white mineral oil (98%) at 23 oC (the standard temperature for the test). If I ...
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1answer
24 views

How significant is air decomposition on NOₓ formation?

How significant is $\ce{NO$_x$}$ formation from $\ce{O2}$ (reactant) and $\ce{N2}$ decomposition from simply heating the two as opposed to from $\ce{CO2}$, $\ce{H2O}$, (and $\ce{N2}$) dissociation? In ...
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1answer
68 views

Write the combustion equation of C5H10O

Like the title, have no idea at all, can someone help me? Should I add $\ce{O2}$ to make it $$\ce{C5H10O + O2 → ..... ?}$$ Full process will be really appreciated ! Thanks for your help!
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69 views

Fire resistance of PVC

In a paper that I'm reading, it states that The presence of Chlorine atoms in polyvinyl chloride make it flame resistant and I'm just wondering why the presence of Cl will make it flame ...
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1answer
60 views

Why is CO a major species only in fuel-rich combustion?

In fuel-rich combustion, my understanding is that enough fuel reacts and consumes all of the oxygen present. The combustion products $\ce{CO2}$ and $\ce{H2O}$ undergo dissociation until equilibrium is ...
5
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1answer
98 views

Is There a Difference in the Definition of Complete and Stoichiometric Combustion?

My question has to do with some combustion related definitions. When the term complete combustion is used, is it assumed that the combustion is stoichiometric (reactants combine perfectly), but ...
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1answer
199 views

Combustion of paraffin

Find the heat of combustion for 1 mol of $\ce {C21H44}$ in the reaction where some wax is oxidized to elemental C (soot) and water vapor. The Heat of Formation of $\ce {C21H44}$ is -476 kJ/mol. When ...
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114 views

Relationship between Auto-Ignition Temperature with Pressure and Fuel

Experimentally it appears that increase in pressure, fuel concentration, and chain length causes AIT to decrease until a minimum where even further increase in these parameters increases the AIT. ...
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1answer
39 views

Greatest Energy Output Reaction to Atmosphere Air

First of all i'm no chemist, this is not homework and if you need further clarification please ask. I'll be happy to provide! Imagine that you: have 1 kg of any given chemical X A car battery A ...
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30 views

Additional Questions Regarding the Auto-Ignition Temperature

I had some followup questions regarding a previous post I made here regarding the auto-ignition temperature and ASTM E659 For fuel temperature below AIT, we should still have finite reactants above ...
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1answer
151 views

Mechanics Behind the Auto Ignition Temperature

I have some questions about the auto-ignition temperature for fuels. Per ASTM E659: AIT (auto-ignition temperature) is the lowest temperature at which the substance will produce hot-flame ignition ...
2
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329 views

Relationship between Equivalence Ratio and Adiabatic Flame Temperature for Fuel Rich Combustion

I'm reading a combustion text and would like help interpreting the following passage (diagram attached). It is regarding the relationship between equivalence ratio and adiabatic flame temperature: ...
7
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1answer
115 views

Do reverse reactions occur in combustion?

I am currently reading a textbook on combustion. They assume that all reactions go to completion, such that post combustion only unburned fuel/air and actual products remain. Assuming that combustion ...
7
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1k views

Heats of combustion and stability of rings

Can anyone explain why? If you think about it, without having the data of the heat of combustion of each type of bond, you can't really answer this question. I know that cyclopropane has a higher ...
4
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1answer
143 views

Heat of combustion for Octane

I'm a Mechanical Engineering student and I have been working on a school project but I want to go a bit beyond that and it has led me here. I'm designing an engine cylinder, and I figured I should be ...
8
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3answers
114 views

What really happens atomically in an explosion?

Let's say a room is filled with butane, I then throw a cigarette into the room. What happens to the atoms/molecules of the butane when they are in contact with the heat from the cigarette?
3
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1answer
144 views

Black Smoke Produced from Regular Lighter but Not Torch Lighter Applied to Copper

I have a piece of copper mesh from which I would like to remove all coatings/oils. The copper comes from a pot scrubber like this. In order to remove any residue, I held a standard bic lighter up to ...
2
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2answers
960 views

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 ...
2
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1answer
109 views

What is the mole fraction in mixture before combustion?

What is the mole fraction of $\ce{C2H6} / \ce{C3H8}$ in mixture, if both compounds reacted with $\ce{O2}$ in stoichiometric ratio? Mass of produced $\ce{CO2}$ is $1.819$ times larger than the mass of ...
8
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1answer
282 views

Why is there sulfur in black powder / gun powder?

Black powder is composed of charcoal, sulfur and a nitrate salt. The charcoal and sulfur serve as fuel and the nitrate is the oxidizing agent. However, wouldn't it be cheaper to leave out the ...
2
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1answer
128 views

Can electrolyzing ice cause an explosion?

I know electrolyzing water separates it into hydrogen and oxygen. However, I am curious, if ice is electrolyzed, could it explode? My thought process is that oxygen and hydrogen bubbles would build ...
3
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1answer
89 views

I heard aluminium doesn't produce fumes when burnt but the opposite happened, how?

One day I took aluminium foil(sanitary brand, don't know if you've heard it) then I casually burned it over a gas lighter then it burned and gave off Grey fumes and the foil became a dull Grey ...
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1answer
101 views

Questions about combustion and isotopic abundance

the combustion of 0.214g of sulfur provided exactly 0.428g of sulfur dioxide. After a second try, 0.782g of SO2 was obtained. What mass of sulfur was used? The combustion of lithium forms lithium ...
4
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1answer
67 views

Can water be ignited in an ozone atmosphere?

According to my calculations, the reaction $\ce{H2O + O3 -> H2O2 + O2}$ should be favourable under standard conditions. However I am told that the reaction is probably very slow in solution since ...
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99 views

Ingestible Chemicals to cause “spontaneous human combustion” [closed]

Apologies if this isn't the right SE site to ask this, but after reading the very thorough answer to whether spontaneous human combustion exists on Skeptics.SE, and the statement that In forensic ...
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33 views

Heat of combustion per mole and per kilogram

I need to calculate the heat of combustion per mole and per kilogram of complete combustion of, say, X. I write reaction : $\ce{X + O2 -> ... + Q}$ Find Q using Hess law Now, what do I do after ...
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2answers
826 views

Reaction involved in Combustion of Nitrocellulose-Nitroglycerine(NCNG) solid propellant?

I'm working on solid propellant based microthrusters and I am using NCNG as the solid propellant. I want to know the reaction taking place and the mass fraction of the products obtained on combustion ...