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).
446
questions
6
votes
1
answer
477
views
"Fireblob" in KO₂ and PCl₅ reaction
The reaction between $\ce{KO2(s)}$ and $\ce{PCl5(s)}$ leads to the strange formation of a black "fireblob" which eventually turns orange.
This is demonstrated in this YouTube video (...
- 315
-5
votes
2
answers
172
views
How do I calculate the fuel consumption inside a cylinder-piston stoichiometrically?
Consider I have car 4-cylinders with total cylinder capacity is 1,496cc. Per piston, the cylinder is 374cc. The piston diameter is 72.5mm, height=90.6mm, and compression ratio is 11.5:1. Hence we may ...
0
votes
0
answers
34
views
Specific temperature ranges of kinetic combustion mechanisms
Do kinetic combustion mechanisms typically operate within specific temperature ranges? I tested some mechanisms from the scientific literature, and apparently they were only working at temperatures ...
-4
votes
1
answer
59
views
Can this equation be balanced using ion-electron method?
Reaction:
$\ce{C2H4 + O2 → CO2 + H2O}$
I want to balance the above reaction using the ion-electron method.
My attempt:
Ox-half: $\ce{C2^(^-^2^)H4 + 4H2O → 2C^(^+^4^)O2 + 12H^+ +12e^-}$
Red-half: $\ce{...
2
votes
1
answer
205
views
Why is coal and charcoal a good fuel, but not graphite?
Correct me if I'm wrong, but coal(after coking) and charcoal are essentially hard dry lumps of pure carbon.
But of course so is graphite. I understand of course the structure is different lending them ...
- 129
1
vote
0
answers
24
views
Exothermic Rapid Multistage Reactions
I asked a similar question on SpaceExploration, but I think it might be better answered here:
Most chemical reactions in rocket combustion sequences are fairly simple, even with "exotic" ...
- 119
1
vote
1
answer
76
views
Combustion of organic materials in oxygen-18
Suppose I have some material that came from or was made from a plant or animal. I will assume that its molecular structure, along with carbon, will contain some oxygen as well as other elements. If I ...
- 21
2
votes
2
answers
56
views
Risk of spontaneous combustion with cedarwood oil
Is there a risk of spontaneous combustion of cedarwood oil used with rattan diffuser reeds as in the photograph at the bottom?
An NFPA safety sheet talks about the risk of spontaneous combustion of &...
- 127
-1
votes
1
answer
79
views
Creating a Simplified Model for Temperature Change in Auto-Ignition of A4 Office Paper [closed]
When paper reached a certain temperature, auto-ignition occurs, and then there is a process that makes the temperature rise to around 1000 to 1500 Celsius degrees. How can I make a simplified model ...
- 3
-3
votes
1
answer
71
views
Can someone help me with the experimental tabulation or spread sheet data on enthalpy, temperature, and pressure for aluminum and oxygen combustion [closed]
I need an experimental tabulation or spread sheet data of enthalpy, temperature, and pressure tabulated in columns for aluminum and oxygen combustion under non standard conditions.
Any references to ...
- 15
4
votes
1
answer
114
views
Chemical species equations in a kinetic mechanism of combustion
In combustion, for a kinetic mechanism involving $m$ reactions and $n$ chemical species, of the form
\begin{align}
\begin{cases}
\nu_{11}' \mathcal{S}_1 + \nu_{12}' \mathcal{S}_2 + \dots + ...
3
votes
1
answer
1k
views
Striking back of Bunsen burner
I have a question about striking back of Bunsen burner, regarding the reaction between methane and oxygen.
When methane gas reacts with oxygen completely, a clean non-luminous blue flame can be ...
-2
votes
1
answer
145
views
What range of relative humidity is present in the combustion byproducts of a natural gas stove, immediately after combustion?
If I have a traditional gas range-top, burning natural gas (instead of LPG or propane), what is the typical range of humidity present in the combustion byproducts immediately above the flame? The ...
- 123
4
votes
2
answers
578
views
Flash point of naptha and propanol
I filled a Zippo lighter with 2-propanol and it lit up easily when the ambient temperature was around 6-7 degrees Celsius.
It was impossible to light it up when the temperature was around 3-4 degrees ...
- 149
0
votes
0
answers
45
views
Combustion of Sodium (Na) Metal in presence of Excess Air [duplicate]
There was a question which I was recently solving regarding the products formed after combustion of Sodium Metal in presence of Excess Air.
The given answers were Na2O2 (sodium peroxide) and Na2O (...
- 91
1
vote
1
answer
602
views
How does burning natural gas produce nitrogen oxides?
I understand that the byproducts of burning methane to be carbon dioxide and water, and in low oxygen situations, carbon monoxide.
$\ce{CH4 + 2 O2 -> CO2 + 2 H2O}$
$\ce{2 CH4 + O2 -> 2 CO + 4 H2}...
- 113
3
votes
0
answers
46
views
How stable are paper book matches?
I have few hundred paper book match books that I collected about 25 to 45 years ago when many businesses had them custom printed.
They are from around the world although mostly US. They are in an open ...
- 3,719
0
votes
0
answers
55
views
When hydrogen and oxygen reacts, what defines if it will turn into hydrogen peroxide or water?
If you have a jar with oxygen and hydrogen inside, I'm interested in knowing what variables are most important to ensure that the mixture will become water (if that was the goal) or hydrogen peroxide, ...
3
votes
1
answer
146
views
Are solid fuels with calorific values >= 10,000 kcal/kg (42 MJ/kg) physically possible?
I have seen laboratory documentation from a reputable lab in southeast Asia that a company has achieved a solid fuel product made from landfill material with a high heating calorific value ($CV$) of ...
- 490
-3
votes
2
answers
106
views
Is there an intuitive answer why burning is very exothermic? [closed]
Water and carbon dioxide are much lower in energy than hydrocarbon and oxygen. Is there an intuitive answer for this? Is this because atom arrangements that have more polar bonds tend to be lower in ...
- 199
2
votes
1
answer
129
views
What chemicals can remove or greatly reduce the smell of burning diesel fuel?
I am not a chemist myself but I am trying to solve a practical problem I am experiencing.
I have a nicely working diesel stove but it produces some smell.
I've read that adding urea to the exhaust may ...
3
votes
1
answer
164
views
How can combusted methane from landfill samples be quantified?
Background:
For my studies I'm wanting and attempting to make a landfill greenhouse gas emissions (GHG) model that predicts the amount of greenhouse gas equivalent emissions ($GHG_\mathrm{eq}$ [tonnes/...
- 490
6
votes
3
answers
1k
views
Does stoichiometric gas mixture produce the highest explosion pressure (or energy) compared with other explosive limit mixture?
I understand that a stoichiometric mixture contains a balanced mixture of air and fuel and both fuel and air are completed consumed. For example, the ideal stoichiometric mixture for propane is ...
- 81
-2
votes
1
answer
201
views
What's the stoichiometric ratio of Kerosene to a mixture of 50% water and 50% hydrogen peroxide [closed]
So I'm wanting to do some testing with combustion of certain liquids, and I'd like to know what the right ratio is for these liquids. What I'm going to be using is regular kerosene (NOT RP-1) and 50% ...
- 1
6
votes
2
answers
369
views
Equilibrium constant vs Reaction rate constant
For a reaction, e.g.,
$$a X + b Y → c Z$$
Its reaction rate constant is
$${\displaystyle r=k_f(T)[\mathrm {X} ]^{m}[\mathrm {Y} ]^{n}}$$
where the exponents m and n are called partial orders of ...
- 81
-4
votes
1
answer
64
views
What happened after fire finished burning? [closed]
After fire finished burning, did it merge with the atmosphere and becoming water vapors, oxygen and nitrogen, or did it simply disappear into nothing?
- 101
1
vote
1
answer
71
views
Understanding Hydrocarbon Combustion [duplicate]
First ... I know almost nothing about chemistry.
So, for the past week or so, I've kind of been fascinated with this whole combustion thing (not in an evil way, of course). So, I've been reading, and ...
- 121
0
votes
1
answer
1k
views
What compounds smell like burning rubber or tar?
Background:
A couple of friends of mine live next door to each other in a 10-year old block of flats in London, UK. They say that in the early hours of the morning, a toxic smell appears in their ...
- 169
1
vote
0
answers
24
views
Aproximation of H2 combusion limits
I'm looking for a relatively simple approximation for combustibility limits of H2/O2/N2 gas mixtures over temperature/pressure. (It doesn't need to be conservative.)
I've found a fair bit of data for ...
- 111
0
votes
0
answers
43
views
Understanding uni- and termolecular reactions in combustion kinetics
I'm trying to understand and incorporate 9-species 19-reaction H2/O2 combustion mechanism into my numerical solver. The reaction mechanism in question is O'Conaire. It seems that the paper is in some ...
- 111
0
votes
0
answers
35
views
Could perchlorate salts allow for underwater combustion?
So apparently perchlorate salts can act as oxidizers for combustion (basically they can replace oxygen in the fire triangle, at least I think), and the reason why you can't have a fire underwater is ...
3
votes
0
answers
95
views
Are carbon nanotubes and graphene very flammable?
The reason I ask is because carbon is quite flammable in virtually every shape we encounter in nature. Even diamonds burn as a matter of fact. And after I just saw some steel wool burn easily, I ...
- 151
0
votes
2
answers
106
views
Is it possible to modify how energy is released in the combustion of a fuel like methane? [closed]
From what I understand (please correct me if I'm wrong), combustion is an exothermic oxidation reaction where, for example, a fuel like methane is combined with oxygen, i.e. CH4 + 2O2 → CO2 + 2H2O. My ...
- 111
5
votes
1
answer
954
views
Why would tellurium + sodium hydroxide have worked as a good anti-knock gasoline additive (if it wasn't so smelly)?
The April 22, 2022 Veritasium video The Man Who Accidentally Killed The Most People In History mentions several aspects of the historical use of tetra-ethyl lead in gasoline, the resulting widespread ...
- 5,742
-1
votes
1
answer
89
views
What is the most stable cycloalkene? [closed]
I'm looking specifically at cyclopentene and cyclohexene. Supposedly, greater instability would lead to a more exothermic enthalpy of combustion. However, based on my data, cyclopentene is more ...
- 3
2
votes
0
answers
46
views
Origin of oxygen content among the products of burned carbohydrates
For simplicity, I am only considering complete combustion.
I am ignoring variants such as deoxyribose, just pure carbohydrates.
Balancing the equation is easy due to the definition of carbohydrate: we ...
- 818
1
vote
0
answers
66
views
How much heat is exchanged by this system?
I am having trouble with the following question:
We allow $\pu{18 g}$ of oxygen to react with $\pu{23 g}$ of ethane. The reaction is shown below. Since the heat of combustion of ethane is $\pu{-1560 ...
- 21
0
votes
1
answer
65
views
How holes in cooking burner help it to perform complete combution but candle thread can't by providing sufficient oxygen supply?
Recently I was introduced to organic chemistry for the first time.
In the section of complete and incomplete combustion of carbon compounds,
they provide example of two different objects, namely a ...
2
votes
3
answers
225
views
Do molecules containing enough oxygen to burn themselves exist?
Is there a molecule with enough oxygen in it (for example, something like $\ce{HCOOOH}$) such that it can undergo complete combustion without requiring any additional oxygen? For example the above ...
- 171
3
votes
0
answers
55
views
Is the activation energy higher in incomplete combustion or in complete combustion?
I am looking into high school level chemistry where it is asked if the incomplete combustion of methane into carbon monoxide has a higher activation energy then its complete combustion.
My reasoning ...
- 131
7
votes
1
answer
2k
views
Where does the energy from combustion come from?
I am aware that combustion reactions are exothermic. The energy stored in the chemical bonds of the products is less than the energy stored in the chemical bonds of the reactants. The difference in ...
- 187
18
votes
3
answers
3k
views
What is going on in and below a yellow or blue gas flame?
Unsure if this is more chemistry or physics, but here goes...
Consider a Bunsen burner and the flame it produces when the air inlets are closed vs open.
According to the description on the linked ...
- 425
1
vote
3
answers
155
views
Does smoking drugs degrade them?
Why doesn't smoking a drug degrade or destroy it?
A wide variety of psychoactive compounds ("drugs") are commonly consumed via smoking – e.g., nicotine, THC, amphetamines, cocaine, and DMT. ...
- 3,290
0
votes
0
answers
44
views
Why do hydrocarbons give out a blue flame on complete combustion? [duplicate]
In complete combustion of hydrocarbons the colour of the flame is blue. But what is the reason behind the flame being blue and not green or black or any other colour?
Edit: I've searched the web for ...
- 332
2
votes
0
answers
54
views
Why is the the temperature change due to the combustion of paraffin wax so high (10000 Kelvin)? [closed]
I'm trying to work out the temperature change (I got something like 10k Kelvin,hotter than the Sun's core...) caused by the combustion of paraffin wax which has a molar enthalpy of combustion $E^{wax}...
- 139
1
vote
2
answers
837
views
Combustion analysis of hydrocarbon
Combustion analysis of a hydrocarbon produced 33.01 g CO2 and 4.84 g H2O.
I was asked to find the empirical formula of the hydrocarbon. I used these molar mass values for my calculations:
C - 12.0107
...
- 29
-2
votes
1
answer
102
views
Looking for gas or liquid for story research
I am working on a story for adaptation into animation. Main lead is a chemist in a traditional fantasy setting. The chemist uses her own compound to battle using fire or explosions. I love the ...
6
votes
2
answers
566
views
Why do alkenes (olefins) burn hotter than alkanes (paraffins), even though alkanes are denser and more hydrogen-rich?
Burning hydrogen releases more total energy than combusting carbon, and all alkanes are denser as well, so why are flame temperatures for alkene molecules higher than their equivalent alkanes?
P.S.: ...
- 1,793
2
votes
0
answers
65
views
What is the coolest known flame? [duplicate]
Inspired by this youtube demonstration by ChemicalForce, I'm prompted to ask what is the coldest possible flame.
What the video seems to show is phosphorus vapour in an inert gas being blown into air. ...
- 35.4k
-1
votes
2
answers
172
views
Balancing octane combustion reaction for internal combustion engine
I am trying to balance out the equation for combustion of octane in $120\,\%$ of excess air with products $\ce{CO2},$ $\ce{H2O},$ $\ce{N2},$ and $\ce{O2}$:
$$\ce{C8H18 + 1.2$a$(O2 + 3.76 N2) -> $b$ ...
- 155