April 09, 2020, 12:59:09 AM
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High School Chemistry Forum / Thermodinamics Equations of State
« Last post by domingo2000 on Yesterday at 07:20:40 PM »
Hi, my question is the following, if I need to find the parameters of an equation of state in function of the Critical Conditions, hoy many times can I calculate the partial derivative and make it equal to 0, for example, to find the a and b of the van der waals equation of state, with the first and second derivative equal to 0 you can find the parameters inf function of the critical conditions (Pc,Tc and Vc).
In a homework i have an equation of state of grade 4 and i dont know if a can calculate the third derivative and make it equal to 0
2
Organic Chemistry Forum / Re: Organic Chemistry Mechanisms
« Last post by Babcock_Hall on Yesterday at 06:53:56 PM »
Welcome to the forum.  It is a forum rule (see red link above) that you must show your attempt before we can help you.
3
Organic Chemistry Forum / Organic Chemistry Mechanisms
« Last post by nyarlathotep on Yesterday at 05:14:54 PM »
Hello,

I'm currently studying organic chemistry mechanisms for a upcoming exam and i need help with the following problem (view attachments).

Basically i need the solution for the whole thing. Rvery product and the mechanism the originated them.

Thanks in advance.
4
Organic Chemistry Forum / Re: Carbonyl, Cetal + TsOH
« Last post by hollytara on Yesterday at 05:03:34 PM »
You start with a ketal of acetone.... 

You "exchange" this ketal for the ketal of the other ketone - an intramolecular ketal.
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High School Chemistry Forum / Re: Percent alcohol in DIY hand sanitizer
« Last post by xxxCarlxxx on Yesterday at 04:53:47 PM »
Thank You!
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Organic Chemistry Forum for Graduate Students and Professionals / Re: Drying a solution of zncl2
« Last post by CrazyGoat on Yesterday at 04:44:21 PM »
I will rewrite my question:
I have to do a reaction free of water and O2.
For that I will use a reflux system in which all glass has been previously dried under vacuum and where a constant flux of argon is going on.
This reaction must be done with zncl2 which is highly hygroscopic,
I have bough it anhydrous and it is sealed but I will have to open it, and add it to the flask.
Will it in this moment get a lot of atmospheric water?
I pretend (once the flask is closed again)
flame dry it again, but this time with the zncl2 inside. (for remove added moisture in the flask + the one in the zncl2)
But according to the zncl2 literature
Heating the "hydrated" form, ZnCl2•n(H2O), yields Zn(OH)Cl, not ZnCl2.
My question here:
If (in this particular case) I flame dry it under vacuum and have got some water particle in the process of letting it inside of the flask...
The hydroxide gas will just go away by the pump suction and only will remains pure anhydrous zncl2 that I can use for my dried reaction, with out lossing, by the little watter adquiered in the short time of hadeling it, too much of the active zncl2 while been oxigen free.
So no a big deal.
Or it's a big deal?
Thank you.
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Organic Chemistry Forum / Re: drying glacial acetic acid
« Last post by wildfyr on Yesterday at 04:24:27 PM »
If there is, say, 0.2% water in there, then adding acetic anhydride and distilling it all seems pretty painful. Its 500 mL I think.

I guess I could add a little acetic anhydride then just distill a small amount of acetic acid as I need it.

I wonder if I could do the trick where I reflux it with the setup is rbf under open addition funnel containing of sieves with a condenser on top of that. The reaction to adsorb most of the water is pretty fast, but aldol condensation on the sieves takes some time. After letting it reflux under the sieves for a while, I can then reduce the temperature and run a reaction in the rbf on the bottom.
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High School Chemistry Forum / Re: I need help on this local exam problem
« Last post by Fudjsk on Yesterday at 04:13:01 PM »
My bad I'll do it next time.
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High School Chemistry Forum / Re: I need help on this local exam problem
« Last post by billnotgatez on Yesterday at 03:39:08 PM »
You have to show your attempts or thoughts at solving the question to receive help.
This is a forum policy.
Click on the link near the top center of the forum page.
Forum Rules: Read This Before Posting.
http://www.chemicalforums.com/index.php?topic=65859.0
10
Undergraduate General Chemistry Forum / Re: Help with a buffer question
« Last post by Borek on Yesterday at 02:27:03 PM »
https://www.chembuddy.com/?left=buffers&right=pH-change
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