May 09, 2021, 06:04:25 PM
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So can hydrogen bonding be considered a specific type of dipole-dipole interaction?
"Dipole-dipole interaction" suggests interaction between permanent or induced dipole, while molecule (donor or acceptor) can be completely non-polar. It just need polarized -H bond for donor and lone pairs on O or N atom for acceptor.
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"H is bonded to a small electronegative atoms like flourine, nitrogen or oxygen". Isn't that strange that it uses the word 'like'? Are there any other small electronegative elements that could be included in this definition?
S, Cl and Br can also act as acceptors.
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What's going on with SbH3, in that it has a higher boiling point than NH3?
It's like give wings to an elephant - it is still too heavy.
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High School Chemistry Forum / Re: Need Help Replicating a Solution
« Last post by ACETAT on Today at 04:31:15 PM »
You dont need NaCl you need NaOCl.
If no knowledge  dont make it by yourself. And dont do  electrolysis with mixtures of acetic acid and sodiumchloride. Dangerous.
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Analytical Chemistry Forum / Re: Old sealed glass stopper bottles?
« Last post by Borek on Today at 04:09:32 PM »
The blue/green liquid one has some blue crystals and blue powder at the bottom. Looking around on the web I was thinking Copper Sulfide???

Sulfate. But if there is a green tint it can be something else as well.

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Anyway, I noticed that my eyes have to been itchy and sneezing/coughing more than usual.  Do you think I purchased some dangerous chemicals?

No. Doesn't mean they are absolutely safe, but as long as you treat them with some respect (no eating, drinking, gloves, glasses etc) it is quite unlikely you have something really toxic/explosive. That being said, many chemicals can be irritating, which is why they are typically kept in fume hoods. Keeping them at home is not a good idea, getting rid of them is not trivial.
 
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(Ok, not letting me post photos.... that sucks)

You probably need to resize them so that they are not too large.
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Hydrogen bonding is basically the same thing as dipole-dipole forces? It's just that the atoms H, O & F make these dipole-dipole forces stronger. So can hydrogen bonding be considered a specific type of dipole-dipole interaction?

In my book it says it's when "H is bonded to a small electronegative atoms like flourine, nitrogen or oxygen". Isn't that strange that it uses the word 'like'? Are there any other small electronegative elements that could be included in this definition? Like Sb? What's going on with SbH3, in that it has a higher boiling point than NH3?

Please post straight forward answers.

Thank you
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Organic Chemistry Forum / Re: surprising answers for Sn2 vs Sn1
« Last post by Meter on Today at 03:31:26 PM »
Also, I didn't mean to insinuate that rolnor didn't know what hyperconjugation is. It was a geniune, open-ended question.
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Organic Chemistry Forum / Re: surprising answers for Sn2 vs Sn1
« Last post by Meter on Today at 03:30:02 PM »
I agree with you, I would say d is possibly a mixture of Sn1 and Sn2 and b is pure Sn2. But also, acetic acid is a unusuall solvent so one has to look in the original paper, if there is one.
Carbocation stability depends on its ability to hyperconjugate with adjacent atoms. Can hyperconjugation occur between molecules?

When Rolnor says "mixture of Sn1 and Sn2", they mean two separate pathways/mechanisms. I am sure they know what hyperconjugation is.

For example, if the experimental outcome is 80% inversion and 20% retention, this could be explained by a mixture of different mechanisms. Unfortunately, this could also be explained by some kind of ion pairing argument, and other things maybe like a reversible Sn2, so there would need to be some other data to be sure.

Thank you for your input, Rolnor. If I can, I will contact the writer of the question and see if they have a reference. This would be a crapshoot, as it is possible they just made it up off the top of their head.
It's most likely just a brain fart then. I don't see how SN1 could proceed on a primary alkyl halide unless some exotic chemistry was going on. Maybe the author ment to but the Br on the second carbon, where SN2/SN1 are both possible, but ultimately the nucleophile/solvent decided?
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Organic Chemistry Forum / Re: surprising answers for Sn2 vs Sn1
« Last post by OrganicH2O on Today at 03:23:33 PM »
I agree with you, I would say d is possibly a mixture of Sn1 and Sn2 and b is pure Sn2. But also, acetic acid is a unusuall solvent so one has to look in the original paper, if there is one.
Carbocation stability depends on its ability to hyperconjugate with adjacent atoms. Can hyperconjugation occur between molecules?

When Rolnor says "mixture of Sn1 and Sn2", they mean two separate pathways/mechanisms. I am sure they know what hyperconjugation is.

For example, if the experimental outcome is 80% inversion and 20% retention, this could be explained by a mixture of different mechanisms. Unfortunately, this could also be explained by some kind of ion pairing argument, and other things maybe like a reversible Sn2, so there would need to be some other data to be sure.

Thank you for your input, Rolnor. If I can, I will contact the writer of the question and see if they have a reference. This would be a crapshoot, as it is possible they just made it up off the top of their head.
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High School Chemistry Forum / Need Help Replicating a Solution
« Last post by joshua1892 on Today at 12:55:12 PM »
Hi Everyone, I need some help replicating a solution that I don't want to have to keep buying from the manufacturer.  I use the solution to make a half gallon (2 L) of Hypochlorus Acid for cleaning.  I have some basic chemistry knowledge but not much.  The solution comes in 2.4 fl oz (3.0 wt oz) packets and state active ingredients of 25.88% Sodium Chloride and 74.12% other ingredients. I know one of the "other" ingredients is Glacial Acetic Acid.  I'm assuming I messed up the math.  My plan was to calculate out the sodium chloride, add it to the water and then add Glacial Acetic Acid until the PH's match. I came up with 18.37 g NaCl to 71 ml water. If I take 71 ml of water and mix in 18.37 g sodium chloride, it seems like it's too much.  The solution from the company is completely clear, and even heating the water I can't get that amount of salt to dissolve in that amount of water where it comes out clear.  I'm not sure if I should subtract the amount of water that is equal to the amount of salt in my solution either, but in my head it makes sense to do so to make the overall amount of the solution stay the same.  The company's solution has a PH of 2.65 @ 20.1 degrees C.  I'm also adding anywhere from 1 to 2 ml of the Glacial Acetic Acid to get the PH's to match.

I've been at this for probably a year now just slightly modifying the ingredients, but after mixing the 2.4 oz solution of water, NaCl and Glacial Acid to the half gallon of water and doing electrolysis the Hypochlorus Acid solution I make never comes out to match the 1100 ppm total available chlorine that the company's solution creates.  Can someone point me in the right direction please?   

Thanks!
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Analytical Chemistry Forum / Old sealed glass stopper bottles?
« Last post by KatJ on Today at 11:51:07 AM »
I am Not a chemist.
I found some very old large glass apothecary bottles at an antique shop in Tucson yesterday. For some reason I bought them.
The ground glass stoppers are sealed on two of them. They don’t budge. The blue/green liquid one has some blue crystals and blue powder at the bottom. Looking around on the web I was thinking Copper Sulfide???  The clearish one has some white crystals at the bottom.  The purple tinted one is empty and the glass stopped is removable. It has a white residue toward the top of the bottle.
Anyway, I noticed that my eyes have to been itchy and sneezing/coughing more than usual.  Do you think I purchased some dangerous chemicals?
I also read about old liquid Ether in bottles that end up exploding!
Here are a few photos:
(Ok, not letting me post photos.... that sucks)
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Undergraduate General Chemistry Forum / Re: Reaction types
« Last post by Pat79 on Today at 09:35:23 AM »
Cool..that clears up a lot. It seemed very confusing as there were so many cases that didn't fit.

Would you be able to recommend a good book for learning? or websites?
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