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).

Filter by
Sorted by
Tagged with
4
votes
3answers
5k 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 ...
1
vote
1answer
608 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
votes
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
votes
1answer
13k 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, ...
8
votes
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
votes
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 ...
2
votes
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 -> ...
4
votes
0answers
79 views

What happens when I divide two molar flow rates in a chemical equation?

I don't quite know how summarize my question in the title. I have a combustion process given by this equation: $$\ce{C10H22 + 15.5 O2 + 58.25 N2 -> 11 H2O + 10 CO2 + 58.25 N2}$$ This process ...
2
votes
0answers
140 views

Is it true that when hydrogen reacts with oxygen to form water, that if first forms an hydroxyl radical? [closed]

When I took chemistry in high school, the inevitable question as to whether or not water has a chemical name came up. Our instructor said no, but if it did it ought to be called hydrogen hydroxide. ...
4
votes
3answers
2k views

Why is it wrong to calculate the amount of oxygen directly from the products of a combustion reaction?

I've been stumped by a question in my textbook concerning combustion analysis. A $\pu{0.5438g}$ sample of a liquid consisting of only $\ce{C}$, $\ce{H}$, and $\ce{O}$ was burned in pure oxygen, ...
10
votes
3answers
473 views

Why does internal combustion engine smoke appear blue? Could there be “blue molecules” in it?

Four-stroke and two-stroke gasoline engines as well as diesel engines can all emit dense clouds of blue-tinged smoke under various transient loads or incorrectly tuned conditions. Raleigh scattering -...
1
vote
1answer
126 views

Reacting carbon dioxide with magnesium in ribbon form

My experiment involves a reaction of magnesium in ribbon form with that of carbon dioxide. I know that the product shall be magnesium oxide (white powder) and carbon (black powder) but I do not know ...
4
votes
1answer
700 views

Can hydrocarbons undergo combustion without oxygen present?

Most of us are familiar with the standard reaction of methane gas combustion: $$\ce{CH4 + 2O2 -> CO2 + 2 H2O}$$ In standard combustion, oxygen is generally used as the oxidant. Would it be ...
3
votes
1answer
45 views

Can an improvised torch be made to last for a prolonged period of time?

In the movie First Blood, there is a scene where Rambo is trapped in a cave after escaping a bazooka rocket that caused the mine he was hiding in to collapse. After realizing the entrance has been ...
1
vote
2answers
92 views

Can we chemically characterize a flame? [closed]

Can we chemically characterize a flame ? Recently, while I was lighting a candle, I came across this question; can we find out the chemical composition of a particular flame? If yes then how? In ...
0
votes
1answer
416 views

How does the degree of saturation influence the colour of the flame?

If the colour of flame produced by the atom of an element is the property of that element then why do unsaturated and saturated carbon compounds give different colours of flame even though both ...
3
votes
1answer
322 views

Does benzene vapor react with air in a closed barrel?

If we would have benzene in a closed barrel for quite a while at room temperature, some vapor would form fast due to its volatility, right? But let's say that when the barrel was closed, some air got ...
3
votes
2answers
2k views

Is liquid hydrogen rocket propeller pollution free?

If one searches for the different fuel types used in rockets, one can find that over the years, NASA and other space agencies have used both solid fuels and liquid fuels. I can see that more and more ...
4
votes
2answers
2k views

Why should fire extinguishers containing carbon dioxide not be used on magnesium fires?

As the title states, why should $\ce{CO2}$ fire extinguishers containing carbon dioxide not be used on fires with magnesium metal? I understand that $\ce{CO2}$ extinguishers work by displacing oxygen,...
1
vote
3answers
708 views

Calculating standard combustion enthalpy of dodecane from that of heptane & octane

These are the problem from UKChO-2015. Given the standard enthalpy changes of combustion ($\Delta_\mathrm{c}H$) for heptane ($n = 7$) and octane ($n = 8$) are $-4816$ and $-5470~\mathrm{kJ~mol^{-1}}...
0
votes
3answers
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 ...
12
votes
3answers
8k views

Why is the outermost part of the Bunsen burner flame not the hottest region?

Why is the blue flame the hottest on a Bunsen burner? I thought the outermost part of the flame must be the hottest region because of complete combustion of gases taking place there. Where am I ...
2
votes
0answers
59 views

How much energy can be produced by burning sewage gas?

I am an eighth grader. I need to make a science project on the production of electricity from sewage. I know that almost sixty percent of sewage gas is Methane and most of the other constituents are ...
25
votes
1answer
1k views

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. ...
2
votes
0answers
101 views

Chile 2017, One of the Largest Fires in South America: Wood Ash Derivates for Industrial Applications [closed]

Hi: We're a group of people who wants to help people, domestic animals and wildlife recovering from this fire. Summary: We're having in Chile one of the largest fires in South American history. More ...
12
votes
1answer
1k views

Can diamond undergo a self sustaining combustion reaction all the way to carbon dioxide?

I know charcoal can smoulder in an incomplete combustion to produce carbon monoxide so I assume diamond also can. If it's heated to a sufficiently high temperature, will the reaction produce enough ...
5
votes
3answers
12k views

Why are hydrocarbon flames yellow or blue?

A candle gives a yellow flame while kerosene gives a blue flame on burning. Now, saturated hydrocarbons give a blue flame but unsaturated ones give a yellow flame. I want to know why the colour of the ...
12
votes
2answers
2k views

How does heptafluoropropane suppress fire?

How does heptafluoropropane suppress fire? It says here that it does so by "inhibiting the chain reaction." What does that mean specifically? Does $\ce{O2}$ attach itself to the heptafluoropropane?...
0
votes
1answer
33 views

If propane with specific parameters were to combust in open air, what is actual volume of CO2 produced

Lets say we have a sample of propane gas having a volume of 2.70 L at standard room temperature and 1.75 atm. This gas is exposed to our air. The equation that governs this reaction is: $mC_3H_8 + ...
0
votes
1answer
1k views

Combustion of non-hydrocarbon organic compounds

When we learned about combustion, we learned about the combustion of hydrocarbons and compounds with only hydrogen, oxygen, and carbon. However, how would combustion work with compounds that contained ...
19
votes
1answer
1k views

How do self-relighting (trick) birthday candles work?

You may have seen those birthday candles, where, upon blowing them out they smoulder for a bit and then (magically) relight. How do they work? Why can't regular candles do this (is it possible for a ...
1
vote
1answer
59 views

Usage of ammonia as odorant in fuel gases

Usually, thiols such as ethanethiol are added to fuel gases to warn the user of a leak. Why is a few percent of ammonia not used instead? Ammonia is flammable so it will burn to nitrogen and water in ...
1
vote
2answers
796 views

Spectrometry in Chemistry & Flame Test Lab

Question 1: You currently see two colors that are two similar (dark yellow and orange) in a flame test lab. And also you have a hard time differentiating the colors, what is an alternative to ...
6
votes
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?
3
votes
3answers
1k views

Why can wood burn all the way to charcoal instead of just creating a passivating charcoal layer?

I know burning to charcoal is actually incomplete combustion because charcoal can also burn. When a strike anywhere match burns, it burns all the way to charcoal but the charcoal doesn't further burn. ...
139
votes
7answers
42k views

Why doesn't water burn?

Hydrogen is flammable, and for any fire to burn it needs oxygen. Why does a compound made of hydrogen and oxygen put out fires instead of catalyzing them? I understand that hydrogen and water are ...
5
votes
2answers
444 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 ...
1
vote
0answers
124 views

Which one is the healthiest to operate a lantern with: kerosene, diesel or sunflower oil?

Given a lantern (originally made for kerosene) however, I'm looking for the fuel which is the safest for indoor use. I've already tried different kinds, and found three of them that burn just as ...
1
vote
1answer
74 views

Are the odours added to natural gas completely flammable?

I live in Australia, where both electricity and natural gas are common forms of household energy. An odour is added to the natural gas as a safety precaution since it is otherwise almost undetectable. ...
1
vote
1answer
149 views

What would an ammonium sulfide fire look like?

I am writing a novel and the climax involves killing my protagonist in an explosion. My science knowledge is poor but I believe my scenario is entirely plausible except possibly a couple of details. ...
0
votes
1answer
3k views

Why isn't CO2 flammable? [closed]

Given that $\ce{CO2}$ is comprised of carbon and oxygen, why isn't it a flammable gas?
0
votes
0answers
139 views

Why would Ammonium Nitrate spontaneously combust/detonate when damp?

Why would small amounts (1g or less) of Ammonium Nitrate spontaneously combust/detonate when damp? Possible temperature excursions to +70degC. Unfortunately I cannot give you the context for ...
1
vote
0answers
96 views

Making solid fuel out of sugar

I recently tried to make a cheap solid fuel out of sugar. First I attempted burning the sugar cube directly, which did not work well even using a blowtorch. This was expected. Then I attempted to use ...
0
votes
1answer
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 ...
3
votes
1answer
8k views

What happens when you 'burn' ash?

This popped into my my mind while watching a match burn (don't ask me what I was doing with a burning match...). Now as I know it, 'ash' is what you call the residual, grey-black powdery material ...
1
vote
1answer
68 views

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 ...
14
votes
1answer
1k views

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 ...
1
vote
2answers
3k views

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? ...
5
votes
1answer
94 views

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?
14
votes
5answers
17k views

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, ...

1 2 3
4
5
8