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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86 views

What substances are hypergolic with liquid O2?

If something flammable is surrounded just by oxygen, I should see flame, right? The object would be even surrounded by more molecules than in the case of gas oxygen. On the youtube I see that people ...
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243 views

Heat of Combustion

Methanol ($\ce{CH3OH}$) is regarded by many chemists as a possible liquid fuel for the future. The combustion of methanol occurs according to the equation: $$\ce{2CH3OH(g) + 3O2(g) -> 2CO2(g) + ...
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Does the ignition temperature of a substance decrease with the concentration of oxygen?

Is it possible for a substance to undergo combustion at a temperature lower than its ignition point if the concentration of oxygen increases?
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Computing the turbulent flame length

There is a problem I found online for practice that I cannot solve: Problem Methane, $\ce{CH4}$, emerges from a $1\ \mathrm{cm}$ diameter nozzle at a rate of $120\ \mathrm{cm^3/s}$ and a mole ...
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3answers
5k views

How much Carbon Dioxide would be required to displace enough oxygen to prevent ignition?

In air, how much $\ce{CO2}$ would be required to prevent a match to light or a butane lighter to work? I have a basement office that is unusable because of an apparent lack of oxygen, currently it ...
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37 views

Why fire spreads out, depending on burning substance, with different speed?

In Action movies, I have seen a couple of times that if flammable gases or liquids like benzene are ignited, the fire spreads out within fraction of a second and sometimes there is also an explosion. ...
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6k views

Combustion of saturated hydrocarbons vs combustion of unsaturated hydrocarbons

I read in my science book that saturated hydrocarbons burn with a blue flame (indicates complete combustion) and unsaturated hydrocarbons burn with a yellow flame (indicates incomplete combustion) due ...
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1answer
39 views

Why doesn't this question violate the conservation of mass?

Combustion of of $0.255 \space g$ of isopropyl alcohol produces $0.561 \space g$ of $\ce{CO_2}$ and $0.306 \space g$ of $\ce{H_2O}$. Determine the emperical formula of isopropyl alcohol. I'm not ...
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360 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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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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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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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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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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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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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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491 views

How does the presence of chlorine atoms in PVC make it flame resistant?

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 chlorine atoms will make it ...
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CH4 + O2 => CO2 + 2H2, what's wrong with it?

It says in my textbook that: $$\ce{CH4 + 2 O2 -> CO2 + 2 H2O}$$ which seems like a displacement reaction to me. Shouldn't the reaction be: $$\ce{CH4 + O2 -> CO2 + 2 H2}$$ since $\ce{4H}$ ...
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1answer
246 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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How to determine the empirical formula for terephthalic acid from its combustion products?

Terephthalic acid is an important chemical used in the manufacture of polyesters and plasticisers. It contains only $\ce{C}$, $\ce{H}$, and $\ce{O}$. In one experiment, $0.4953~\mathrm{g}$ of the acid ...
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704 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
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 ...
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441 views

Oxidation of malonic acid

Question How many grams $\ce{CO2}$ will result when burning $\pu{100 g}$ malonic acid? The formula for malonic acid is $\ce{C3H4O4}$ so 3 $\ce{CO2}$ molecules should result from oxidating one ...
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109 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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569 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 ...
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Write the combustion equation of an organic compound

Write the combustion equation of the organic compound $\ce{C5H10O}$ I have no idea at all how to write the equation. Should I add $\ce{O2}$ to make it $$\ce{C5H10O + O2 → ... ?}$$
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753 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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205 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
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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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62 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
204 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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152 views

Combustion of halo-organic compound

My question is based on the Preparatory Problem Set for the 47th IChO Problem 26 - Holy War against Four Horsemen of the Apocalypse (it is on page 36). It is written that cooling of Y combustion ...
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377 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,...
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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
606 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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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
109 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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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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3k views

Why is compressed air flammable?

I have a can of compressed air. The type you use to clean the insides of computer. It's "100% ozone friendly" and "pure compressed gas". So I assume its everyday regular breathable air. I used it to ...
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584 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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493 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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224 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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1answer
944 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 ...
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2answers
371 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 ...
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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
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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1answer
110 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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4answers
2k views

Is oxygen necessary for burning?

Is oxygen really necessary for burning things? What if there was no oxygen around? Would there still be a way to burn things?
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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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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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168 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 $...

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