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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Smoldering Combustion

Does smoldering combustion only occur in an environment where oxygen levels are low? Will it always transition into flaming combustion (whenever there is ample supply of oxygen? Or can it keep ...
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How can solids undergo combustion if it only occurs in the gas phase?

According to the smoldering Wikipedia article, flaming combustion occurs in the gaseous phase. I know butane undergoes flaming combustion in a Bunsen burner because it's a gas, but how can wood ...
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What is the empirical formula of the polyethylene?

Polyethylene is a polymer of only carbon and hydrogen. If 2.300 g of the polymer is burned in the oxygen it produces 2.955 g H2O and 7.217 g CO2. What is the empirical formula of the polyethylene? ...
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Why don't the products of combustion stop combustion?

We know that combustion of fuels give water and carbon dioxide (during combustion of hydrocarbon) as a byproduct, but why don't these byproducts stop combustion?
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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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1answer
268 views

Release of sulfur dioxide from odored fuel gases

Often, fuel gases such as butane and natural gas (methane) are mixed with some foul-smelling impurities such as thiols (mercaptans) and hydrogen sulfide. Presumably, anything containing sulfur would ...
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How to calculate the amount of substances product produces from the masses and amounts of starting materials?

Calculate the amount of carbon dioxide formed when we burn 1 mole of carbon in the presence of 16 g of dioxygen. $$\ce{C + O2 -> CO2}$$ 1 mole of carbon means 12 g. Therefore amount of ...
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Incense Stick vs Candle

*Not sure whether to put this on Phy or chem.. * What exactly happens when you light an incense stick? How is this different from a candle, or embers for that matter? From what I understand, a ...
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Propan-1-ol Heats Objects Faster than Propan-2-ol. Is this an anomaly?

After conducting a practical revolving around burning alcohols, I found that propan-1-ol heated the 50 mL of water to 60 °C about 1 min faster than propan-2-ol. The experiment was controlled as much ...
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Sugar burning with the assistance of ash

If a plain pile of sugar (or a sugar cube) is heated with a torch, it just melts and gives off smoke. However, if some paper or wood ashes are added, it burns quite easily. What are the ingredients of ...
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Incomplete combustion

I cannot find a definitive equation that describes the incomplete combustion of a hydrocarbon. Equations $1$, $2$ and $3$ are some of the variations I have found. Is it, $(1)$ $\ce{C_xH_y + O_2 \...
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Is a gas leak considered incomplete combustion?

This may be a dumb question, but if I leave the stove-top valve open (or I have a gas leak due broken tubing), would that be considered incomplete combustion? From my knowledge, I figured a reaction ...
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Relating to combustion

Can i make a gel/liquid/any kind of solution which supports combustion but at the same time protect the surface from getting burnt? I wanted to light a log on fire using some kind of fuel which allows ...
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Why don't we produce water from combustion?

My friend who is a biology major proposed that we can produce water by burning any hydrocarbure or wood or ... to obtain water. $\color{red}{f(x,y,z,\Lambda)}\ce{C}_x\ce{H}_y\Lambda_z+\color{red}{g(...
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Does any known substance ignite on cooling?

As the title says, I'm interested in knowing if there is any substance — or combination of substances — that ignites (or even increases its chance of spontaneous ignition) when cooled. I've never ...
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Given a theoretical combustion engine, how can I calculate the output of this engine depending on the fuel it uses?

I'm writing a Minecraft mod (for those who don't know, it's sort of like a smaller "program" that loads into the Minecraft game and expands it, by adding other things to it). My question is: consider ...
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How is combustion speed regulated in solid propellants?

My question on Space.SE didn't yield anything I didn't know already: the secondary regulation mechanism – grain (cross-section shape) of the propellant, changing the area of open surface of the ...
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337 views

Propane Combustion in a Gas Grill with Irregular Flameouts

I'm troubleshooting a problem with a brand-new propane gas grill that is experiencing flameouts and making puffing/popping sounds. I'm asking here because I want to understand the basic chemistry ...
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Can ethanol alone be used as Fuel?

Ethanol is a clean fuel and added as an additive to petrol. Why can't ethanol itself be used as fuel?
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687 views

Plastics and Cotton

Plastics melt on heating and Cotton burns. When do substances burn with flame? Should they always contain volatile compounds for them to create the Flame?
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ZnO spontaneous combustion during transport

I found your contact information researching $\ce{ZnO}$ reactions. I was hoping you could please help me or orient me in the right direction to find an answer to my problem. The company I work for ...
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Why do the alkali metals form different products upon combustion in air?

From Wikipedia's article on sodium: When burned in dry air, it forms primarily sodium peroxide with some sodium oxide. We know that sodium has a strong reducing capacity, so why does it produce a ...
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How to fake a fireball? [closed]

It is for my book: i need some material, what would burn very bright for a long time, what could it be? Or another advises, how could a character fake a fireball, seen in the sky for a long time?
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How much “cleaner” does summer fuel burn?

Well, it's that time of year again: the switchover to "summer" fuel and resulting price increases. This EPA regulation system requires gasoline producers to blend additives into the gasoline that ...
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Gases produced by pyrolysis of cellulose

I heated cotton in a sealed container (with a small hole) over a natural gas flame. Some gases and smoke were produced. What would they probably be? I can come up with some guesses based on the ...
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Density of LPG in g/L [closed]

What is the density of LPG (in vapour state) in g/L? Please note that I'm asking about the density of vapour LPG when it comes out of the cylinder. NOT the liquefied density!
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Why there is an Upper Explosive concentration Limit?

If we have a mixture of combustible gas (let's say it's methane) and air, what is the physical explanation for having a upper concentration limit? I found this document: Lower and upper explosive ...
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112 views

How can I obtain oxygen gas from plagioclase

I would like to know if there is a possibility to decompose plagioclase to obtain oxygen gas to be used in a combustion reaction? I know that oxygen represents $47\%$ of the weight of 1 mole of ...
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93 views

Combustion that generates no gas?

I'm learning on my own with Chemistry The Central Science, 13th ed. book. So far it's going well. I've come across something I don't think I understand. I've googled and "stackechanged" with no avail....
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Combustibility of gas/carbon dioxide mix

Via electrolysis I produced an ethane/hydrogen/carbon dioxide mix. Normally, there is 1 part ethane, 1 part hydrogen and 2 parts carbon dioxide. If I simply used a Bunsen burner with air hole closed ...
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430 views

Exhaust gas purification

I'm more asking this because I'm not sure how far science has come. Pretty much, I've been thinking about the car exhaust system lately. The two main components that lead to hazards from cars are $\ce{...
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544 views

Output of the Sugar & Sulfuric Acid Reaction?

When a reaction of sugar and sulfuric acid occurs, some form of carbon is produced. Is this carbon bonded as graphite? If not, than what is it bonded as? $\ce{C6H12O6 ->[H2SO4] 6C + 6 H2O }$
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What causes transition from smoldering combustion to flame combustion?

What causes the transition from smoldering combustion to flame combustion? From what I have read about it is that, smoldering combustion gives off a lot of flammable gases, primarily, Carbon Monoxide,...
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Meaning of Flammability Limits and reaction in Air of Ammonia

I have read on Wikipedia that the flammable limits of gaseous ammonia are between 15–25% and I have also read that the autoignition temperature is $651\rm~^\circ C$. And that the combustion of ...
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Why do unsaturated hydrocarbons burn with a sooty flame while saturated hydrocarbons burn with a clear flame when burnt in the air?

Why do saturated hydrocarbons burn with a clean flame while unsaturated hydrocarbons burn with a sooty flame when burnt in air? My chemistry book says that it happens due to the amount of carbon ...
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249 views

Why are fires smokey?

Combustion, in chemical terms, is a reaction with a certain molecule and oxygen, and it produces, energy, $\ce{CO2}$, and $\ce{H2O}$ (That's how I learned it at least). So what makes a fire'smokey'? I ...
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275 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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Why does shaking a match put the fire out?

Move a match slowly and nothing happens but if you shake it violently the fire will extinguish. Oxygen makes fire grow so why does waving a flame through the oxygen rich air put the fire out? Does ...
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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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Can oxidizing agents act as comburents?

Comburent, to the best of my knowledge, refer to substances that catalyze combustion reactions without reacting itself or being flammable independently, such as potassium chromate. How would oxidizing ...
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What's the composition of gun smoke and is it dangerous?

Background I've been conducting an informal (i.e. mental) risk assessment of visiting gun ranges. There are a couple of obvious sources of hazard: Injury by bullet Hearing loss Hot casings flying ...
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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 makes a glowing splinter glow and a burning splinter burn

This question bugs me for years since I started learning the oxygen, carbon dioxide and hydrogen tests. I know you can make a glowing splinter burn when doing the oxygen test due to enough oxygen. But ...
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What is the meaning when it is said “Temperature of an Oxyacetylene Torch is 3500 degrees Celsius”?

I don't think flame is anything but the product at that temperature but I am not sure. What exactly is flame? And I think the correct statement should be that the exothermic reaction here produces ...
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Controled burn colored fire and safety

I am a martial artist who uses fire weapons in my shows. I am wondering how I can get the flames to be different colors. I've done some research about it, and have found that the salts of some ...
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203 views

What proportion of a combustion engine's output energy comes from the air?

When trying to compare the efficiency and range of electric engines vs gasoline engines, it seemed at first that gasoline had a higher energy density than batteries. But then I realiced that a ...
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Heat of combustion of stereoisomers of 1-tert-butyl-2,4-dimethylcyclohexane

Which of the compounds below has the smallest heat of combustion? I know that the heat of combustion is indirectly proportional to the stability of a molecule. And here both $\ce{CH3}$ and $\ce{C(CH3)...
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Why do branched hydrocarbons burn more efficiently (complete & clean combustion)?

Branched and cycled hydrocarbons usually a higher octane number than their straight chain counterparts. This is due to a more complete and clean (no residue) combustion. In addition, there is no ...
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About how much carbon monoxide is produced in these two different reations?

The U.S. Department of Agriculture produces a gas cartridge to poison subterranean rodents. The product is provided as a cardboard tube sealed at one end and then loaded with a mixture of 144.6 grams ...
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To what degree an N99 active coal filter can protect against products of burning paraffin oil?

I sometimes do firedance and a part of it is waving a stick with burning endings made of Kevlar soaked in paraffin oil. I started to be a bit concerned about how healthy is it to inhale lot of ...

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