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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A sealed container contains 90 % hydrogen and 10 % oxygen. There is a spark in the container. What happens? [closed]

A sealed container contains 90 % hydrogen and 10 % oxygen. There is a spark in the container. What happens? Assuming it is a 10-litre volume container like a fuel tank.
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How does the vapor pressure in a vessel affects the total pressure after a combustion reaction?

The problem is as follows: A sealed container of $3\,L$ in capactity is filled with hydrogen and oxygen at $314\,torr$ each one at a temperature of $27^{\circ}C$. A spark produces the reaction ...
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What is the result of the combustion of the mixture?

I prepared a little experiment about solid rocket propulsion. I have used water ($H_{2}O$), potassium nitrate ($KNO_{3}$) and saccharose ($C_{12}H_{22}O_{11}$). I made the mixture in a pan by cooking ...
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How do I balance the combustion reaction of butene?

I have butene being burned in a fuel rich engine and I can't seem to balance this reaction: $$\ce{C4H8 + $a$(O2 + 3.76 N2) -> $b$ CO2 + $c$ H2O + $d$ C4H8 + $e$ (3.76 N2)}$$ When I try write ...
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Why does a wood fire create benzene?

According to this article called The Fireplace Delusion a wood-fire will create benzene. This surprised me and I can't find an article online that explains the chemical reaction behind that.
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How to determine the composition of a gas mixture after a combustion?

The problem is as follows: A mixture of gases consisting of $\ce{CH4}$ and $\ce{C2H4}$ is let to pass over red hot $\ce{CuO}$. Then $\pu{0.6g}$ of $\ce{H2O}$ is collected along $\pu{1.185g}$ of ...
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Colored Flames Experiment

I am going to be doing a gender reveal for my sister's pregnancy. To do this, we wanted to light a huge fire pit and throw in a chemical to change the fire into the color (red/pink for girl, blue/...
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Is it possible to obtain the amount of air required for a combustion analysis?

I'm not very sure if the required amount of oxygen (I assume) can be found by only knowing the amounts of the produced subtances after a combustion. To illustrate this I found this problem: $1.14\,...
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What is behind of the attraction between a burned matchstick with a magnet?

I do not know how to understand the reasons of why a burned matchstick is attracted by a magnet (most probably) of Neodymium. Here are some screenshots of a video in which this natural phenomenon is ...
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Equation of combustion of heavy fuel oil (HFO)

We are researching the use of heavy fuel oil (HFO) on ship vessels, but are having trouble finding the equation of the chemical combustion process of HFO. I understand that it contains long chains of ...
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What temperature is required to burn pencil lead graphite?

I tried to burn a bunch of 8B pencil lead in a gas flame the other day. None of it actually caught fire, but being made of carbon (in the form of graphite) should cause it to burn, as graphite is ...
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Is it possible to have a negative overall activation energy for a whole reaction mechanism?

I am trying to find out correlation for ignition delay for alkane fuels. The activation energy part of the correlation gives me a negative value. For the ignition delay formulation, is it possible to ...
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Fires with chlorine

could a fire with it's fuel consisting of mostly carbon like coal or wood use chlorine instead of oxygen. My thinking goes that when fire burns it sucks in oxygen and that bonds with carbon to make ...
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Why polyethylene (PE), wool (polyamide) and cotton (cellulose) burnt with different smells, while they just product CO2 (and N2)?

Both PE and cotton produce CO2, but they distinctly have different smells while being burnt (Burning PE has smell of candle wax, while burning cotton’s smell is like burning leaves). Wool produces CO2 ...
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Does combustion occur more easily at higher oxygen concentrations or just higher oxygen partial pressure?

I saw a trailer for The Martian and started thinking about space flight. I know that spacecraft and spacesuits often operate at low pressure with high oxygen content (near 100% $\ce{O2}$ at about 20 ...
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Calculating ΔH with non-integer coefficients in the balanced equation

I am working a practice problem out Ebbing's General Chemistry and for part of the problem I needed to calculate $ΔH.$ The problem considers the burning of ethane in oxygen to yield carbon dioxide and ...
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Hess's Law and ΔH

Target equation: $\ce{Mg(s) + 1/2 O2 -> MgO(s)}$ $$ \begin{align} \ce{MgO(s) + 2 HCl(aq) &-> MgCl2(aq) + H2O(l)} &\quad ΔH &= \pu{-1300 kJ} \tag{1}\\ \ce{Mg(s) + 2 HCl(aq) &-&...
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Why is the outermost part of the Bunsen burner flame not the hottest region?

Why is the blue flame the hottest on a Bunsen burner? I thought the outermost part of the flame must be the hottest region because of complete combustion of gases taking place there. Where am I ...
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Heat of combustion among substituted cyclohexanes

Arrange in ascending order of heat of combustion: I know heat of combustion is inversely proportional to stability. Also, to solve I did try making chair conformations of the substituted cyclohexane. ...
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Heats of combustion and stability of rings

Which isomer would have the largest heat of combustion? A) Propylcyclopropane B) Ethylcyclobutane C) Methylcyclopentane D) Cyclohexane E) Since they are all isomers, all would have the same heat of ...
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Incomplete Combustion products

In class we performed an experiment which I am unable to understand the results for Why does the the amount of soot produced vary? What is the amount of soot produced dependent on? Experiment: ...
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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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Why are hydrocarbon flames yellow or blue?

A candle gives a yellow flame while kerosene gives a blue flame on burning. Now, saturated hydrocarbons give a blue flame but unsaturated ones give a yellow flame. I want to know why the colour of the ...
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Combustion and pyrolysis of sulfides and organosulfurs

Last week there was a huge fire in french chemical factory Lubrizol, we now know the main products that burnt, to simplify the discussion I extracted a few compounds: isobutyl and isobutene ...
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Why are wet things harder to ignite than dry things? [closed]

Specifically wood and paper and other hydrocarbons, but not necessarily excluding other things that burn. We all know wet wood is very hard to ignite. Wetness here refers to water. But why is that ...
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Based on their respective number of degrees of freedom, what's the most efficient fuel; hydrogen or gasoline?

The reaction of octane's combustion is: $$\ce{2 C8H18 + 25 O2 -> 18 H2O + 16 CO2}$$ I am asked for computing the number of degrees of freedom of the octane given that its specific heat is $\pu{...
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Are all volatile liquids combustible?

I realized that liquids like petrol, kerosene and even perfumes are combustible when they are volatile. Could that be the reason why water is not combustible is because it is not volatile? Are ...
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Why does hydrogen burn with a pop sound?

Our teacher made us to do an experiment with zinc granules and hydrochloric acid. $$\ce{2HCl + Zn -> ZnCl2 + H2}$$ We collected the hydrogen gas that was evolved in a test tube and on ignition, ...
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Using an oxidizing agent to improve combustion of a fuel [closed]

If I were to add an oxidizing agent like dilute Potassium permanganate (aq) to a potential fuel such as plastics (polystyrene etc), would the combustion of this fuel be more complete ie: less sooty ...
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Air contain 20 % O2 by volume. How many cm³ of air will be required for oxidation of 100 cm³ of acetylene?

Air contain 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: equation:...
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Is combustion considered a redox reaction?

When carbon combusts with oxygen, is this considered a redox reaction since the oxygen atoms gain electrons and the carbon atoms lose them?
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What Is The Heat Of Combustion Of Diesel And How Do I Find It? [closed]

I need help in finding the heat of combustion of diesel, no where online can i find it, and my chemistry teacher does not know how to find it....
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How do you find the heat capacity ratio of combustion products?

For example, if gaseous oxygen $(O_2)$ and paraffin wax $(C_{32}H_{66})$ were to stoichiometrically combust at STP, how would one go about finding the heat capacity ratio ($\gamma={c_p \over c_v}$) of ...
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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 230 °C (the standard temperature for the test). If ...
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The phlogiston theory [closed]

I have looked this theory up on google and found that the theory is that when metal is burnt calx (metal oxide) and phlogiston is created (metal --> calx + phlogiston). Then I found out that ...
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2answers
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Why doesn't natural gas combustion release only one-sixth as much carbon dioxide as coal burning?

Burning hydrogen releases a little more energy than burning carbon, correct? And methane is CH4, but coal is mostly C, correct? So shouldn't burning pure carbon release five times the CO2 (Assuming ...
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2answers
145 views

Will mixing hydrogen and oxygen without a spark result in combustion? [duplicate]

I plan to do the electrolysis of dilute sulphuric acid. This will produce hydrogen gas and oxygen gas at the anodes. I do not plan to collect these gases, but to simply let it form and release into ...
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1answer
379 views

Why does microwaving napalm make it nonflammable?

In this video, microwaving napalm made it nonflammable. What caused this to happen? I assume it was some sort of chemical reaction. Could someone explain? I understand some chemistry, but a not-too-...
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What would happen if you burned paper with a laser, in a vacuum?

If you hit a piece of paper with a powerful laser inside a vacuum, what would happen? It sounds like it should not "burn" and have a flame spread over the paper, as there is, of course, no oxygen. ...
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How do fuel/oxidizer combustion mechanics change when the constituents are supercritical?

The problem to solve is this: I want to create a heat generator [or heat absorber] that functions at atmospheric pressure to the pressure at the bottom of the sea. It will be used to drive a Stirling ...
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1answer
57 views

Complete Combustion of Inorganic, Hydrogen Containing Covalent Compounds in the Atmosphere

From what I've seen in alkanes, their complete combustion creates carbon dioxide, which has carbon in its highest possible oxidation state. I've been wondering what complete combustion would look ...
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About Smoke Grenades and Sugar Rockets

The most common formula for smoke grenades and sugar rocket fuel is $60\%\ \ce{KNO3}$ (potassium nitrate) and $40\%\ \ce{C12H22O11}$ (sugar). This is a 3:2 ratio, but I've also seen 2:1 and 5:3 with ...
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Why are lower alcohols less flammable than their corresponding alkanes?

How to compare the general trend in amount of combustion in lower alcohols? (upto five/six carbons) Does the branching or straight chain have any effect on combustion?
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Molar heat of combustion with different fuels

I'm not sure exactly how to attack this question, I'm sure that you have to use equations such as $$Q=mc\,\Delta T$$ $$n=\frac{M}{m}$$ But I don't know where to use them. Any help would be ...
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Rate law of the reaction of propane with oxygen

In class, I have a demonstration where I light a bubble filled with propane. As I add oxygen, the bubbles combust faster and more quickly. I have already balanced out the chemical reaction like so: $$...
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264 views

Can carbon subnitride be used as a fuel with similar properties to gasoline?

I am trying to figure out if Dicyanoacetylene, aka carbon subnitride, aka $\ce{C4N2}$, can have a similar reaction with air as gasoline, or if it only creates a lot of heat but not much expansion? As ...
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2k views

Is flour or baking soda really suitable for extinguishing grease fires?

I think most have heard the advise that you should put flour (or baking soda) on a grease fire to absorb the oil before. While this is certainly better than using water, I'm skeptical. For starters ...
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How to capture the gas produced by combusting alcohols

I am burning various alcohols and am attempting to capture the carbon dioxide produced. I could burn the alcohols in a conical flask with a cork on the top, with a tube directing the gas into a gas ...
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210 views

Complete combustion of mixtures

I am working on my scholarship exam practice (around high school and first year university level). I could actually solve the problem below but my solution is pretty time consuming. It would be ...
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Can flames be colored black?

Most of us here would know that flames can be colored by adding an appropriate salt to the 'fuel' or by simply introducing it into a flame. Boron and Barium salts give the flame a green tinge, ...

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