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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7
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1answer
110 views

Why doesn't the carbon dioxide produced by a fire put out said fire?

Carbon dioxide ($\ce{CO2}$) is used in some fire extinguishers to put out fire, but a combustion reaction itself produces $\ce{CO2}$. Why do we get fire then? $$\ce{CH4 + O2 -> CO2 + H2O}$$ Why ...
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1answer
81 views

More effective fire extinguisher liquid than water

I join robot fire fighting contest. One of the mission is to extinguish candle by spraying it with liquid (water is default option). For spray mechanism I use pump with Venturi effect principle. Is ...
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1answer
40 views

Polluting agents generated by road traffic in a city [closed]

I want to measure the air quality according to road traffic in a city. What are the polluting agents (generated by fuel combustion) strictly related and generated by road vehicles that is worth ...
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1answer
256 views

Can glucose burn in chlorine?

Chlorine is an oxidizing agent, so could it replace oxygen? If so, what would be the products, and how much energy would such reactions release? Do any other carbohydrates burn in chlorine? I cannot ...
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1answer
1k views

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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1answer
33 views

Can the pyrophoric tendencies of a pyrophoric substance be suppressed in a pressurized environment?

It's common knowledge that the pressure of an environment influences many properties of a substance, like the melting point, boiling point, or triple point. Pyrophoric substances ignite spontaneously ...
2
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1answer
110 views

Combustion at 298K

Question: (source IITJEE 1992) An aliphatic thiol undergoes combustion at 298K to give carbon dioxide, water and sulfur dioxide. What are the physical states of the products?(solid/liquid/gas) I ...
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1answer
362 views

How can we separate carbon monoxide from wood gas?

I am thinking about using open source wiki designs from allpowerlabs to construct a wood gas generator. The motivation came from experiencing a 10 day power outage after super storm Sandy. The ...
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0answers
574 views

Reaction rate constants for methane combustion

I can't find a rate constant or activation energy for the methane combustion reaction given by: $$\ce{ CH4 + 2O2 -> CO2 + 2H2O}$$ Do all reactions have a rate constant? The NIST web site lists ...
8
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1answer
754 views

What chemical can cause such a fire? [closed]

A friend of mine who thinks that she is under influence of black magic met an astrologer. The astrologer asked her to wear a t-shirt for three nights and then bring that to him. The astrologer then ...
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1answer
208 views

Can oxidation of hydrogen happen in room temperature? [duplicate]

Here is my explanation about the reaction between hydrogen or methane and oxygen. Hydrogen molecules and oxygen molecules can collide sucessfully and react if they have enough energy. In room ...
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1answer
24 views

How do you work out the amount of energy which will be released when a substance undergoes combustion in a pure oxygen environment [closed]

For instance, if we have an abundance of pure Oxygen and one kilogram of Hydrogen and all the Hydrogen reacts with the Oxygen to form H20, how do you work out the amount of energy which will be ...
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2answers
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Can carbon monoxide from a floor-heater in a poorly ventilated room eventually be ignited by the fire and explode?

I have often wondered about carbon monoxide accidents caused by free-standing heaters burning in a poorly ventilated room causing fatalities. I am aware that CO is explosive between 12 and 75% volume ...
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2answers
205 views

Carbon tetraradical

I was just reading through Reactions: The private life of atoms by Peter Atkins and I noticed that in Chapter 3, the chapter on the combustion reaction, the author writes: As we watch we see $\ce {...
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4answers
2k views

Would the concentration of oxygen around fire increase as we get close to the fire (from the outside)

Since fire require oxygen, wouldn't a fire, like those in the American forest along west coast, constantly draws in oxygen from around? And if that is so, would the concentration of oxygen around the ...
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0answers
419 views

Calculate work done by burning benzoic acid exposed to the free air

I'm self-studying and can't solve this problem in Ball's Physical Chemistry. Now, the errata shows that the answer in the book is not correct; still, I can not make sense of it. $(2.55)$ Benzoic acid,...
4
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2answers
182 views

Are all highly shock sensitive chemicals highly temperature sensitive too?

I found that some highly shock sensitive explosives like lead azide, mercury fulminate have a relatively high auto-ignition temperature. I want to know if it's a general property or not and why so? ...
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1answer
2k views

Why are some materials more flammable than others? [closed]

Wood and oil are flammable materials, but water isn't. Moreover, flames spread a lot faster in oil than in a piece of paper. What is the reason that it is so? I also don't know why a small flame can ...
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1answer
611 views

Propane-water molar ratio [closed]

Propane gas, $\ce{C3H8}$, burns in oxygen to produce carbon dioxide and water vapour as follows: $$\ce{C3H8 (g) + 5O2 (g) = 3 CO2(g) + 4 H2O (g) + \pu{2200 kJ}}$$ If $\pu{1.5 mol}$ of propane is ...
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0answers
42 views

Magnesium combustion heat [closed]

When you are going to burn magnesium you need to wait a few seconds before it actually starts to burn. To get to this point it needs a certain amount of energy/heat. How much does it need?
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1answer
110 views

How can pressure build up in an equimolar gaseous reaction? [closed]

To make the question concrete, if you conduct a reaction like $\ce{H2 + Cl2 -> 2HCl}$ in a stoppered test tube, the stopper will aggressively pop off (or the glass will shatter) despite the fact ...
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0answers
592 views

What is wrong with my enthalpy calculations?

I need to calculate the enthalpy of combustion for butane using bond formation energies. Thus I first balance the equation: $$\ce{C4H10 + 6.5 O2 -> 4 CO2 + 5 H2O}$$ Then, I calculate the total ...
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0answers
63 views

Can I approximate the CO concentration of a combustion product, if I know the CO2 and O2 concentration?

Assume I have the product (exhaust gas) from a combusted air/petrol mix. The mixing ratio was richer than stoichiometric (i.e., air:fuel < 14.67 in this case), so there was no excess of oxygen. I ...
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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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0answers
188 views

Which (carbonaceous) fuels produce more or less soot in a diffusion flame, and how to predict that?

From what I've read, the production of soot in a flame is still an open research topic. But some hydrocarbon fuels produce much more soot than others. Are there (simple) rules that tell which fuels ...
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1answer
496 views

Oxygen required to burn carbon [closed]

What volume of oxygen at standard temperature and pressure (STP) is required to burn $2.4 \,\rm{g}$ of carbon to completion?
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0answers
227 views

Is brass combustible in high pressure oxygen environment?

Some metals are particularly ignitable in high pressure oxygen environments, like stainless steel and aluminum. Copper and nickel, on the other hand will self-extinguish when ignited. Does anyone know ...
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2answers
2k views

Is a combustion necessarily a redox-reaction or can there be exceptions?

I have a feeling that I have heard of an exception - either based on the material or the oxidizer.
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1answer
954 views

Finding average Mr of a gaseous mixture

A 2 g mixture of cyclohexanol, acetone and pentanal is completely burnt in oxygen. When the gaseous product is passed through $\ce{P2O5}$, the mass of $\ce{P2O5}$ increased by 1.998 g. Find the ...
2
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2answers
375 views

Spontaneous combustion of sulfur in a steel barrel

Got some free sulfur. Went to the site, and they put a pallet with 3 barrels on it. One of the barrels was badly corroded, but looked like I could get it home. I had plastic barrels at home that I ...
11
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1answer
3k views

What is the difference between ignition temperature and flash point?

I am trying to clarify this for Class 8 Science. Their textbook says "It is the lowest temperature at which a substance catches fire". However, it does not clarify whether it is on its own or due to ...
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1answer
585 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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1answer
4k views

Understanding smoke chemistry of tobacco and/or marijuana

In an effort to understand the effects of tobacco vs marijuana smoke on health, the chemistry of smoking plants, and remembering some of the chemistry I took in college, I came across a 2007 study ...
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0answers
83 views

In a jet or internal combustion engine that burns hydrogen as a fuel, what would happen if you replaced the hydrogen with deuterium? [closed]

Would it increase the power of the jet engine due to heavier atoms being exhausted out the back? For the same reason would it slow down an internal combustion engine?
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0answers
169 views

How to evaluate enthalpy variation of combustion of sucrose in a constant volume calorimeter?

Consider combustion reaction (with the formation of $H_2O$ and $CO_2$) of a mass $m$ of sucrose in a constant volume calorimeter with thermal capacity $C$. This reaction increases the temperature of $...
0
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1answer
165 views

Can hydrogen alone be used as a fuel? [duplicate]

I have always thought that fuel such as petrol, diesel, etc.. are getting burnt to move the pistons in the car (I am not bringing physics). Why not hydrogen be used as a fuel but I know the incident ...
6
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2answers
6k views

Is there a flame which doesn't produce smoke?

I read a book where it states the following: There are many types of flame and there are even flames which don't produce smoke. After reading it, it just got stuck in my mind. Is there a flame ...
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3answers
2k views

Is graphene a combustible material?

Various sources such as https://news.ycombinator.com/item?id=7679154 speculate that graphene will combust at higher temperatures. Is this true? Is the flash point/ temperature of combustion for ...
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2answers
709 views

Why is the enthalpy of combustion higher for n-butane as compared to 2-methylpropane?

N-butane has an enthalpy of formation of $\pu{-125.6 kJ/mol}$, whereas it is $\pu{-134.2kJ/mol}$ for 2-methylpropane. When comparing the heat set free at the combustion process, why is it higher for n-...
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1answer
111 views

Combustion of Rocket-Candy with Fe2O3

We know from Wikipedia that the combustion of rocket candy follow this equation : $\ce{48 KNO3 + 5 C12H22O11 → 55 H2O + 36 CO2 + 24 K2CO3 + 24 N2}$ We can add small quantity of iron (III) oxide ($\...
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0answers
104 views

What would be a suitable non-combustible lubricating oil or compound for a very high pressure air compression system?

This question came up at Engineering SE but remains unanswered. If we are compressing regular air, not nitrogen, what oil or compound can be used that would not combust with the oxygen in the air. ...
3
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1answer
65 views

Aluminium, heat and biological safety

I'm currently working on a really simple project, an ashtray that can stop cigarette combustion. I planned to put an aluminium block into my ashtray, with some kind of curves or holes in it, in order ...
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1answer
2k views

Why does diesel have a higher energy density than gasoline?

One of the primary reasons why hydrocarbons produce energy is the production of water during the combustion process. I've been trying to find out why diesel is considered to have a higher energy ...
4
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3answers
4k views

How do you melt magnesium without causing its combustion?

How do you melt magnesium without causing its combustion? I own a foundry capable of reaching temperatures around 2000 °F, and I recently bought some magnesium for melting before doing my ...
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1answer
581 views

What types of ultraviolet light will ignite hydrogen?

I saw a reaction between hydrogen and chlorine ignite in the presence of UV light. I was wondering if the same thing would happen with something like near-ultraviolet light (around 400 nm). What kinds ...
22
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1answer
8k views

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 ...
6
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1answer
12k views

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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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?
8
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2answers
3k views

Why is oxygen so special?

Why do reactions with oxygen produce flame (i.e. light), heat and hence a lot of energy? I mean, why only oxygen, why not any other element like nitrogen? What is special about the electronic ...
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0answers
65 views

Why won't my propane combust when I spark it?

I need to run an experiment and have some pretty basic questions. I'm trying to get combustion of propane in a controlled environment. I understand that that looks like this: $$\ce{C3H8 + 5O2 -> ...

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