Tagged Questions

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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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
40 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 $CO_2$ and $H_2O$ undergo dissociation until equilibrium is ...
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1answer
58 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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0answers
15 views

Energy of glucose combustion [duplicate]

How much energy is released when glucose burns? I'm using $C_6H_{12}O_6+6O_2−−>6H_2O+6CO_2$ as my balanced chemical equation. I'm making a sugar rocket, and I need to know how hot the combustion ...
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0answers
18 views

Combustion of table sugar (glucose) [closed]

What is the complete reaction for burning sugar? I need the complete reaction in the form A + B --> C + D + $\Delta H$ I want to make a sugar rocket (a small one), but I can't find the complete ...
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1answer
18 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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0answers
39 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
33 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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0answers
25 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
75 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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0answers
77 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
92 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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2answers
240 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 ...
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0answers
49 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 ...
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3answers
75 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?
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votes
1answer
75 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
305 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
62 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 ...
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1answer
124 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
66 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 ...
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1answer
76 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
78 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 ...
3
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1answer
49 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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0answers
59 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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1answer
24 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
378 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 ...
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1answer
52 views

Is the end of a cigarette on fire when lit?

Is the end of a cigarette on fire when it is lit? Or is it smoldering? Is there a chemical difference between the two?
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3answers
217 views

C + O2 is equal to C + O, how is that possible

C + O = CO2 . This is because carbon has valency of 4 while oxygen has valency of 2. When they react the valencies are criss crossed which means we will get C2O4 but this is simplified to CO2. But ...
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0answers
65 views

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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3answers
184 views

Role of heat in combustion

What role does heat play in the combustion process.Specifically, does the amount of heat determine whether complete or incomplete combustion occurs, and is the amount of heat impacted by the amount ...
2
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1answer
51 views

Could this be a feasible fuel system?

First off, please forgive me, I am a chemistry novice! Overall Process Fuel for the system is distilled water Split water into Hydrogen and Oxygen (electrolysis or similar process) Exhaust Oxygen ...
4
votes
1answer
68 views

Maximum pressure that can be produced by a combustion reaction

Multiple-chamber artillery can launch a projectile with energies much higher than single-chamber guns. I'm interested in setting a fundamental upper bound on the energy that a chamber (of a known ...
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1answer
550 views

Limiting Reactants without a given mass

This is a question I have for Chemistry homework, but I don't understand how to solve it without a given mass. I narrowed the choices down (see below _) I know a limiting reactant well limits the ...
0
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1answer
50 views

What would cause a sudden drop in humidity in my home?

I have a ventless propane heater newly installed in my home, which has been an increasingly source of paranoia for me (constant condensation on the windows, worries about carbon monoxide poisoning). ...
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1answer
50 views

What are the known atomic oxygen species?

I'm interested in chemical reaction mechanism with more exotic particles. The Wikipedia page seems to imply that the normal atomic oxygen is $O(^3P)$, is that right? I also came across ...
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0answers
49 views

Calculating mole percentage of a component of a mixture emitted in complete combustion

In a complete combustion (SATP conditions) of $1.00L$ natural gas, there is an emission of 40 Kilo-Joules of heat. If the gas is a mixture of $CH_4$ gas and $C_2H_6$ gas, what is the mole percentage ...
3
votes
1answer
263 views

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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1answer
65 views

Temperature & time necessary to carbonize all organics

Suppose that I have a cast-iron pot which my awful roommate has vigorously scrubbed with soap and left to soak in soapy water over the weekend. The seasoning has been destroyed and replaced with ...
2
votes
1answer
122 views

Variation of cone angle with concentration of fuel-air mixture

A stoichiometric fuel-air mixture flowing in a Bunsen burner forms a well-defined conical flame. The mixture is then made leaner. For the same flow velocity in the tube, how does the cone angle ...
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2answers
724 views

Why is O2 the supporter of combustion?

It's there in every high-school textbook: $O_2$ is the supporter of combustion. Without $O_2$ combustion cannot take place. Why? And why only $O_2$? Why not some other element? And, what happens when ...
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3answers
154 views

Open flame combustion in bizzaro world

Humans typically achieve combustion by starting a chemical reaction of a fuel (often a carbon $C$ containing fluid like methan $CH_4$), which is is brought into an an oxidizer ($O$ containing gas, ...
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3answers
139 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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2answers
797 views

Are there substances that cannot undergo combustion?

Are there substances that cannot undergo combustion? If so, what are they?
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1answer
43 views

What determines a substance's energy of activation with air?

Ice will melt when heat is applied; paper will catch fire. In trying to figure out why — what the difference is between things that melt and things that catch — I found "Burn, Char, Melt" by Roberto ...
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votes
1answer
774 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 ...
4
votes
1answer
108 views

Phenomenon where fumes can relight an extinguished flame

I lit a mosquito coil and used it to melt down small down candle wax which had fallen on the floor. The coil then produced some dense fumes. I directed the fumes to the flame of a candle. As soon the ...
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2answers
548 views

How does sulfuric acid catalyze the reaction of potassium chlorate and sucrose?

Part of the total reaction is mentioned here: http://chemistry.about.com/od/demonstrationsexperiments/ht/instantfire.htm $\ce{2KClO3(s)} + \text{heat} \rightarrow 2\ce{KCl(s)} + 3\ce{O2(g)}$ The ...
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1answer
3k views

Enthalpy Calculations, Heat of Formation/Combustion

I just don't understand how to do these and would really appreciate your help. 1) Ammonium dichromate decomposes in a reaction when heated. Calculate the heat transferred for the decomposition of ...
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1answer
90 views

How can oxygen atoms suddenly appear on the product side of an equation?

The question states the following equation: $$ \ce{C(s) + 2H2(g) -> CO2(g) + 2H2O}$$ And then asks you to calculate the enthalpy change for it, given enthalpies of combustion. The stated values ...
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2answers
155 views

What are the major environmental drawbacks with using methane as a combustable fuel?

What are the biggest environmental issues with using methane, $\ce{CH4}$, (which is found as the major energy source in natural gas, shale gas, biogas, and synthetic natural gas), as a combustible ...