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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72 views

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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4k views

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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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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14 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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18 views

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
25 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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111 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
98 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
45 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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Can a combustion process be more energy efficient with oxygen enrichment?

I wonder if a combustion process with air as oxidant can benefit by oxygen enriching the air intake? By benefit I mean if the net energy output would be positive, or negative, since the enrichment ...
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1answer
153 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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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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1answer
2k views

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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679 views

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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2answers
67 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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1answer
3k 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
4k 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 ...
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1answer
49 views

Water evaporation from calorimeter giving less exothermic enthalpy value?

To find the enthalpy change of combustion for an alcohol, you use a calorimeter filled with water and heat it by burning an alcohol. I was told that usually experimental values for the enthalpy ...
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1answer
69 views

is H2O in gas form in poly styrene combustion? [closed]

original question: if we burn 390g of poly styrene (STP), how much gas produces? me: 1008L my teacher: 672L he says h2o is not in gas form!(because of STP) who is wrong?
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Why is the heat of combustion of sulphur equal to the heat of formation of SO2 and not SO3

By definition the heat of combustion for compound is equal to the energy that is released on complete oxidation of one mole that substance to its highest oxidation state. In case of sulphur, online I ...
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28 views

Determining amount (in mols) of oxygen needed to fully combust coal

I'm trying to calculate the amount of oxygen needed to fully combust some coal. As an example, assume I have $\pu{1 kg}$ of coal which is, by mass fraction, 60% carbon ($\ce{C}$) 40% hydrogen ($\ce{...
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1answer
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What single, pure compound would best replace petrol?

Petrol for use as automotive fuel is produced by blending of different product streams of oil refining. It consists of hundreds of different compounds, and the exact composition can vary widely. ...
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1answer
34 views

Risks of burning melamine formaldehyde adhesives [closed]

Background- I make biochar for gardening, and small scale carbon capture and storage. Most of my feedstock is clean, unpainted, untreated, end of life timber, but there is a small proportion of ...
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2answers
62 views

Sulfates and persulfates as accelerants in black powder?

I saw there was a few black powder posts on here so I'd like to pose a question. Would sulfates or persulfates like the oxidixer soduim persulfate be a good replacement for some percentage of the ...
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3answers
256 views

Is it possible to blow out a candle flame using pure oxygen?

This sounds like a stupid question perhaps, but if a stream of pure $\ce{O2}$ was directed at the flame as a concentrated jet would it blow off the candle?
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3answers
9k views

How can metals like magnesium and sodium burn underwater? [closed]

Please answer with as much detail as possible. I can't find the answer anywhere else and I need it for an essay. Any websites I have found have conflicting answers. One said that they don't actually ...
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0answers
70 views

Adiabatic flame temperature of hydrogen peroxide calculation

I will first demonstrate my cursory method for evaluating the adiabatic flame temperature of H2O2 at atmospheric pressure. $$\ce{H2O2 -> H2O + 0.5O2}$$ At $\pu{1200 K}$, \begin{align} h_\ce{...
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2answers
186 views

Why does old gasoline seem to have more “kick”?

From my personal experience, old gasoline (leftover in a container from the previous year) has more "kick" (power) when I actually use it. Higher idle RPM, higher throttle sensitivity. It says here ...
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3answers
79 views

What is the best way to make a substantial amount of soot in a high school laboratory?

I need to make about 50 grams of soot (carbon black particles) in a high school laboratory. What would be the best way to do this? The purpose of needing 50 grams of soot is because I would like to ...
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3answers
8k views

Is there a point at which Ethanol (E10) fuel becomes harmful to gas tanks or engines if not used?

This is not the typical chemistry question on this website, but I think it's an important practical question. When I got a gas string trimmer, the woman who worked at the gardening shop told me that ...
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5answers
1k views

Can paper burn without oxygen or air?

If you put a paper inside an oven vacuum packed and go beyond $250~\mathrm{^\circ C}$, will it burn? There's no oxidizer. If not, what will happen?
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How can diesel fuel produce less carbon monoxide but more carbon particulates?

My guess at why diesel produces less carbon monoxide is that more heat is required for combustion of diesel fuel, so there is less incomplete combustion. Therefore rather than carbon monoxide being ...
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1answer
2k views

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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Why do highly branched alkanes have higher octane numbers than their corresponding linear isomer?

The octane number of fuels are based on a set of primary reference fuels, which are mixtures of iso-octane and n-heptane. Now iso-octane being branched alkane has very less tendency to react and given ...
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5answers
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Deciding the order of heat of combustion of isomeric alkanes

I'm asked which one of the alkane has the lowest heat of combustion (note: the question says heat, not enthalpy) and according to the answers, the right one is d. I'm trying to understand why d ...
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2answers
40 views

Why does Sodium Bicarb. Reduce Combustion Rate? [closed]

In many common solid-propellant model rocket engines, Sodium Bicarbonate, $\ce{NaHCO3}$, is used to predictably regulate/limit the rate of combustion of the fuel. My questions are as follows: What is ...
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1answer
265 views

Rocket Candy Fuel - Common Alternatives to KNO3?

I'm sort of a model rocket enthusiast, but the most common fuel for model rockets, Rocket Candy, requires Potassium Nitrate as an oxidizer to oxidize Powdered Sugar. Potassium Nitrate is not ...
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1answer
55 views

What is the characterstics of additives that it must posses to make any mixture hypergolic? [closed]

This is about hypergolicity of rocket propellant.Turpentine gave hard-start with RFNA and WFNA but excellent with mixed acid(mixture of HNO3 & H2SO4).Similarly,Furfuryl alcohol & WFNA(also ...
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1answer
310 views

Heats of combustion of cycloalkane homologues

Heat of combustion increases as the number of carbons increases, but on comparing ethyl cyclopentane, ethyl cyclohexane, andethyl cycloheptane, shouldn't you consider ring stability too? In that ...
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112 views

Can someone help me find the limting reagent? [closed]

Okay, so for home work i was given this problem. Suppose that 8.00g of CH4 reacts with 16.00g O2 to form CO2 and H2O, find the grams of CH4, H2o, and O2 left over Balanced Equation : CH4 + 2O2 = ...
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When I burn isopropyl alcohol (IPA), it burns orange. But when I burn ethyl alcohol, it burns totally blue. Why is this?

I burned them in a small aluminium tray. While IPA is burning orange, it produced the smell of soot, but while ethanol is burning blue there isn't any smell. Also, ethanol made the tray really cold ...
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100 views

Are petroleum-based products prone to produce hard residues with black powder?

A common controversy about black powder is lubricant composition. Some people tell this is a bad idea to use any petroleum based products in such lube because it will produce hard, difficult to clean ...
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25 views

Combining enthalpies of formation and combustion in the context of Hess's law

I know that you can use enthalpy of combustion to work out formation, and Formation to work out enthalpy change. But can you use enthalpy of formation and combustion data is the same Hess's cycle to ...
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7answers
4k views

Examples of non-volatile, but flammable liquids?

As far as I know, most flammable liquids are volatile. Are there flammable liquids that are non-volatile?
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1answer
586 views

Is the flame temperature of a burning fuel affected by pre-heating the fuel?

This page on Adiabatic temperatures helpfully lists the theoretical maximum temperatures that flames will reach under certain conditions for a number of fuels. They assume initial atmospheric ...
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2answers
4k views

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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