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35 votes

Five-pointed crown alkane C25H40: does it exist?

These polyspiro compounds such as the one you gave are known as [m,n]rotanes, where m is the size of the central ring and n is the size of the decorating rings. So, your compound would be called [5,5]-...
orthocresol's user avatar
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24 votes
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Cyclobutadiene - Jahn–Teller effect or not?

Very interesting question, and it kept me up despite daylight saving time cheating me of one hour of sleep last night... A good reference is Albright, Burdett and Whangbo, Orbital Interactions in ...
orthocresol's user avatar
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23 votes

How can a molecule with a double bond on one side have a plane of symmetry, and thus, be achiral?

I think this is a case of picture being worth a thousand words. Arguably the easiest way to visualize the plane of symmetry for nonbornene (mirror plane m) is to redraw the molecule in 2D: ...
andselisk's user avatar
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22 votes
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Why doesn't liquid propane in a closed coke bottle burst?

Yes, based on what we can see in the video, your guess appears to be correct: as the propane-filled bottle warmed up, just enough propane evaporated to keep the pressure inside the bottle equal to the ...
Ilmari Karonen's user avatar
21 votes

When I burn isopropyl alcohol (IPA), it burns orange. But when I burn ethyl alcohol, it burns totally blue. Why is this?

IPA has a different carbon:hydrogen ratio than ethanol. There is more incomplete combustion occurring with IPA, hence the smoky orange flame and smell of soot. Ethanol combusts more completely, ...
arevmelikyan's user avatar
18 votes

What single, pure compound would best replace petrol?

Higher $\mathrm{RON}$ seems possible. Yet the boiling point rises accordingly while heat of combustion remains roughly the same. Here are two compounds that fit all posed criteria. \begin{array}{|c|c|...
Linear Christmas's user avatar
18 votes
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ICHO Synthesis Problem 2018

You have asked quite a number of questions in your post so let's tackle it one by one. Why does the oxidation take place at that particular nitrogen atom? To understand this, we first need to ...
Tan Yong Boon's user avatar
18 votes
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When I burn isopropyl alcohol (IPA), it burns orange. But when I burn ethyl alcohol, it burns totally blue. Why is this?

Interesting observation. The blue flame color of all hydrocarbon fuels is due to the emission small diatomic carbon species such $C_2$ or CH. There is nothing magical about IPA having a yellow flame. ...
ACR's user avatar
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18 votes
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Does the largest known cycloalkane contain 288 carbon atoms?

According to Makromol. Chem., Rapid Commun. 1985, 6 (3), 203–208[1], Kwang Sup Lee and Gerhard Wegner, attempting the synthesis and study of $n>100$, $\ce{C_nH_{2n}}$ cyclo-alkanes and linear ...
Safdar Faisal's user avatar
16 votes
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What is the mechanism of alkane combustion?

The following, very general radical reactions apply to any common combustion reaction of organic material. Details vary largely. Step 1 An energy spark of whatever kind turns triplet oxygen into its ...
Karl's user avatar
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15 votes

Does motor oil get more viscous when heated & what is the meaning of the SAE motor oil code?

The numbers in the code have nothing to do with viscosity index. However, your understanding of 'W' for winter is correct. The real code for your car is actually SAE 5W-30 where SAE stands for the ...
Mathew Mahindaratne's user avatar
14 votes
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Why is cyclopropane more acidic than propane

Indeed, according to the Evans $\mathrm{p}K_\mathrm{a}$ table the cyclopropane $\ce{C-H}$ bond $(\mathrm{p}K_\mathrm{a} \approx 46)$ is more acidic than the $\ce{C-H}$ bond on the central carbon in ...
ron's user avatar
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14 votes
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400–430 degrees Celsius heated bath

If it doesn't specifically need to be a hydrocarbon, zinc metal melts at 419.5 °C. Could you do an "ice bath" of zinc chunks in molten zinc, maintaining the melt right at its melting point?
jeffB's user avatar
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14 votes

What happens to the waste products from crude oil refining?

There is also petroleum coke, produced by spraying the very heaviest fractions at high temperature and pressure into a drum to try to eek out any remaining volatile components. The remaining product ...
Joel Keene's user avatar
13 votes
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Is this molecule possible? And if so, what is it called? (Cyclic groups)

If you want to consider the diene as the main chain, you could call this 2-cyclohexyl-1,3-butadiene. This used to be the proper name for the compound, as double bonds used to take priority over any ...
Niels Kornerup's user avatar
13 votes
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Rearrangement with sodium iodide (ring opening)

I think the final product will also contain some Bromine atoms attached to it. and the no. of double bonds will be one less than that of the compound given in the picture. I may be wrong but with all ...
Soumik Das's user avatar
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12 votes
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Is there a reaction to get hydrogen from hydrocarbons?

Hydrocarbons are in fact the main source of hydrogen gas. According to Wikipedia, 95% of all hydrogen is produced by the steam reforming reaction: $$\ce{CH4(g) + H2O(g) -> 3H2(g) + CO(g)}$$ This ...
Nicolau Saker Neto's user avatar
12 votes

Five-pointed crown alkane C25H40: does it exist?

Fascinating molecule. I am not offering anything substantially, new or original here; merely here to confirm what has already been said. I couldn't find any evidence that suggests this particular ...
getafix's user avatar
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12 votes

Why doesn't liquid propane in a closed coke bottle burst?

The person in the video said it was about $\pu{45^oF}$. At this temperature propane has a vapor pressure of about 8 atm, so that is the pressure that built up inside the Coke bottle. Once this ...
airhuff's user avatar
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12 votes
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Can't we reduce climate change by converting CO2 and CH4?

There are a few problems with what you're proposing: The reaction requires energy. Where do get the methane from? What will you do with the carbon you're generating? The energy problem can be solved ...
THelper's user avatar
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12 votes
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What is the 3D shape of an ethane molecule?

You need to know the terms "staggered" and "eclipsed", because that's what we call these two conformations. Now to the point: the real ethane molecule rotates and changes shape all ...
Ivan Neretin's user avatar
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11 votes
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Why do unsaturated hydrocarbons burn with a sooty flame while saturated hydrocarbons burn with a clear flame when burnt in the air?

Your observation that unsaturated hydrocarbons burn with a sooty flame is not always true and depends on the circumstances. There are more factors at play than the nature of the hydrocarbon that is ...
matt_black's user avatar
11 votes
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Why can't terminal alkynes take part in Birch reduction?

The alkyne proton is acidic enough to react with the dissolving metal to give the anion, giving the metal alkynide as it shown by these procedures sodium acetylide prep, sodium phenylacetylide prep; ...
Waylander's user avatar
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11 votes
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Why is the name 'propylene oxide' preferred for epoxypropane?

why is 'propylene oxide' the preferred name for epoxypropane? Propylene oxide is not the "preferred" IUPAC name (PIN): Wikipedia lists the PIN as 2-methyloxirane, which is in line with the 2013 IUPAC ...
orthocresol's user avatar
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11 votes

Does Phenylacetylene undergo side chain oxidation with hot alkaline Potassium permanganate?

According to this source Chemistry Libre Texts Alkynes, similar to alkenes, can be oxidized gently or strongly depending on the reaction environment. Since alkynes are less stable than alkenes, the ...
Waylander's user avatar
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10 votes
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Why does benzyne dimerise and not trimerise?

As per Wikipedia, Biphenylene is quite stable both chemically and thermally, and behaves in many ways like a traditional polycyclic aromatic hydrocarbon. However, both the spectral and chemical ...
Abhigyan's user avatar
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10 votes

Does benzene react with steam to create an alcohol?

Strange as it may seem, benzene can be reacted with steam over a suitable catalyst [1]. The result is a complete breakdown to simpler molecules like methane and carbon dioxide. Typical conditions ...
Oscar Lanzi's user avatar
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10 votes

What is the most acidic neutral hydrocarbon?

In this answer a hydrocarbon anion called Kuhn's anion (1) has the formula $\ce{C67H_{39}^-}$ and reported $pK_b=8.1$, which would correspond to the neutral hydrocarbon having $pK_a=5.9$. The anion, ...
Oscar Lanzi's user avatar
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