May 09, 2021, 05:51:55 PM
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31
Organic Spectroscopy / Re: Combined spectroscopy problem
« Last post by Babcock_Hall on Yesterday at 09:38:53 AM »
I suggest starting with the M+2 peak at m/z 173.
32
Other Sciences Question Forum / Re: Aqueous magnesium sulfate + aqueous barium hydroxide?
« Last post by RonaldKar on Yesterday at 08:07:08 AM »
Calcium Chloride and Magnesium are both from Kent. I have a grounding probe in the sump and a circuit breaker for the whole system. Thanks for your interest jdieck. Its a tough one


(mod edit retain title)
33
Citizen Chemist / Re: Question about yellow plastic chemistry
« Last post by Borek on Yesterday at 07:48:11 AM »
This can be a bit tricky, as often a lot depends on some unpredictable factors - so while I do like the systematic approach and I do agree trying to understand what is really the mechanism of the retrobrite can help in optimizing the process, in the end it can turn out practice/experiment are the only way of finding the best procedure, no matter what the theory says.

Any suggestions for the ratio of Sodium percarb to TEAD?

Stoichiometry would be a reasonable starting point, wouldn't it?
34
Analytical Chemistry Forum / Re: Few questions.
« Last post by Meter on Yesterday at 07:43:08 AM »
You have to show your own attempt before we can help.
35
Analytical Chemistry Forum / Few questions.
« Last post by crunkaintdead on Yesterday at 07:40:26 AM »
1.
When copper is plated on steel, anode is made up of ___.

A) Steel
B)Oxygen
c) copper
D) carbon


2. In electrorefining of copper, 1% of H2SO4 is added to electrolyte  to _______.
A) increase its conductivity
B) increase its dilution
C) DECREASE its conductivity
D) decrease its concentration

3. When the current is passed through an electrolyte solution, which of the following will occur ?
A)anions move towards anode and cations will move towards cathode
B) cations and anions both move towards anode
C) cations and anions both move towards cathode
D)anions move towards cathode and cations move towards anode

4. Which one of the following conducts electricity due to migration of electrons
A) copper metal
B) fused NaCl
C) solid NaCl
D) solution of NaCl

5. Which one of the following is good conductor of electricity ?

A) pure water
B) impure water
C) chloroform
D) none of these




Sorry for bothering and thanks.
36
Organic Spectroscopy / Re: Combined spectroscopy problem
« Last post by luscofusco on Yesterday at 07:23:49 AM »
Yes, I use the slides that the teacher gave us, but I don't understand them very well, and a book. I'll keep working on it, thank you.

37
Organic Chemistry Forum / Re: Trans vs cis stillbene
« Last post by sharbeldam on Yesterday at 07:21:21 AM »
So I get the fact now that cis is more polar, but my inquiry that remains in this synthesis.
if you allow me though, in a specific step of this lab, we get trans/cis isomers and the side product TPPO, so basically two solids and a liquid (cis isomer), to get the cis isomer, can we just used filtration to get the liquid which is the cis isomer, and then we are left with two solids, one is polar and the second is not which is easy to seperate because of the difference in polarity?
38
Organic Chemistry Forum / Re: Scope of Suzuki reagents?
« Last post by rolnor on Yesterday at 06:55:40 AM »
If the boronate is unstable it offcourse matters but if stable the new product will always have the new carbon-carbon bond in the same place as the boron-carbon bond in the boronic ester?
39
Organic Chemistry Forum / Re: Extract measurement
« Last post by Vodkaz on Yesterday at 06:23:32 AM »
I agree, I'll repeat the extraction and see if the problem persists.

Thanks for your remarks
40
Organic Chemistry Forum / Re: Extract measurement
« Last post by Meter on Yesterday at 05:49:07 AM »
Thanks for your response, actually I do not believe that it is a tara problem (I checked the balance a few times), even though, I made the first measurement with porcelain pieces inside the flask, obviously, I left them out of the equation for measurement and it was something like this:

Mass of the extract from round flask: 93.31 g
Mass of the extract after being transferred: 77.49 g

so I am not certain at all if it is just an evaporation issue
Unless you live somewhere exceptionally hot, 25 mL PE is not going to evaporate out of the mouth of a flask in just a few minutes. On a large surface? Sure, but not a flask. Sounds like either a human error or a technical error with the scale. I'd repeat the extraction (being very careful to do everything right) and see if the same problem arises.
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