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Justification for Freezing Point Depression & Boiling Point Elevation in Solutions?
I was wondering if the following justification for freezing point depression and boiling point elevation are conceptually correct. The reason why I ask this question is because I have been self studying chemistry for a course I will be taking this…
Tyreke Davis
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What's the reaction type of the Hydrogen shift?
Rearrangement of cycloheptatrienyl carbene yields heptafulvene via a hydrogen shift.
I see that the reaction is favorable because there is a conjugative effect with the $\pi$ system of the ring in the product.
Does this rearrangement happen by a…
laminin
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Mechanism of carboxylic acid and amide dehydration with phosphorus pentoxide
Dehydration of carboxylic acids with phosphorus pentoxide ($\ce{P2O5}$) yields acid anhydrides, and in a similar reaction, amides dehydrated with phosphorus pentoxide yield cyanides. Can an arrow pushing mechanism be given for these reactions? If…
Charles
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15
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What is the cause of hygroscopy?
Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment.
Why are some compounds hygroscopic and others are not? What is it about their structures that allows them to hold water? Is it due to the…
bohnita
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Inductive effect of phenyl ring
I completely understand how phenyl group 'releases' or 'donates' electron through resonance, but how is that a phenyl group shows a weak -I effect, despite having electrons literally smeared on itself?
Abhirikshma
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15
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By how many pKa units will the pKa value of a ketone be minimized by addition of a Lewis acid
I want to enolize a ketone, for instance acetone with a $\mathrm{p}K_\mathrm{a}$ value of about 20 (in $\ce{H2O}$).
I'd like to know if there exists a rule of thumb to predict how the $\mathrm{p}K_\mathrm{a}$ of the ketone will decrease if we add…
laminin
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15
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Why are noble metals more electronegative then most metals?
I was researching about electronegativity when I looked up what a graph of electronegativity within the periodic table is. And, this appeared. I scanned it, matching up everything I knew about the elements up to that table. Yep, Group 1 is all light…
HyperLuminal
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Why do different elements form different types of carbides?
What property of the elements make them form different types of carbides like:
$\ce{Be}$ and $\ce{Al}$ - $\ce{Be2C}$ and $\ce{Al4C3}$ (Methanides) contains $\ce{C^4-}$ ion
$\ce{Na}$ and $\ce{Ca}$ - $\ce{Na2C2}$ and $\ce{CaC2}$ (acetylides) contains…
Nilay Ghosh
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What color is solid methane?
Is it blueish, perfect white or some other color? I am interested because some celestial bodies are said to be covered with methane ice.
Anixx
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Bond angles for the hydrides
I noticed the fact that all the hydrides of the elements belonging to group IV has bond angle 109.5° while in group V it varies from 107.3° for $\ce{NH3}$ to 91.3° for $\ce{SbH3}$. Similarly we see in group VI that water has highest bond angle then…
Aneek
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Mixing two containers of each water and ethanol to varying degrees of purity
In the following question, the water/wine mixing problem was recast in chemical terms. However, partial molar volumes can make this a much more challenging problem than it appears on the surface.…
Ben Norris
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15
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Are PTFE stir bars resistant to all lab solvents?
It seems like glass-coated stir bars are a specialty item. Standard stir bars are coated in PTFE. Is PTFE resistant to all typical lab solvents? Or is there a reference to check to ensure it is inert to the chemicals being stirred?
feetwet
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Disregarding negative externalities and other barriers, what are some fuels that have a higher power density than gasoline?
Gasoline’s power throughput per kg is $12\,200\:\mathrm{Wh/kg}$ (Wikipedia.org). Are there any other fuels that have a higher power output that are not considered viable solutions as they are difficult to handle or have negative externalities?
Also…
AlanZ2223
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15
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4 answers
Why is HNO3 a stronger oxidising agent than H3PO4?
Why is $\ce{HNO3}$ a stronger oxidising agent than $\ce{H3PO4}$? $\ce{N}$ and $\ce{P}$ have the same oxidation number. Is it the electronegativity difference between $\ce{N}$ and $\ce{P}$?
Ragnar
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What happens if a polymer's length is equal to its persistence length?
So, I've been looking into polymer chemistry to model breaking polymers for a biological model, and I've been a bit stumped by the concept of persistence length.
I know that if a polymer is significantly longer than its persistence length, it needs…
Breaking Bioinformatics
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