Unanswered Questions
466 questions with no upvoted or accepted answers
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Manuals for a Cahn TG-171 Thermogravimetric Analyzer
Recently a Cahn TG-171 Thermogravimetric Analyzer was donated to my school. We did not get a service or user's manual with it, and some of it still needs to be put back together.
I have tried to ...
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9
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0
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Quantitative Transfer of Volatile Standards
(Edited w/ updates) Okay, long story short I work in a lab which has been working on cannabinoid analysis (in the licensed Canadian market) and have had a lot of issues surrounding the standards/...
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Why all commercial SPR instruments use angular interrogation?
Surface plasmonic resonance biosensor devices are used to measure analyte concentration, kinetics, affinity, and specificity without any need for labels. This technique involves the bonding of the ...
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6
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Why is supersaturated sodium acetate so (meta)stable?
Sodium acetate is a common example used in general chemistry lectures to illustrate the idea of supersaturation, and that precipitation of a supersaturated solution can be initiated by a seed crystal. ...
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6
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775
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How can copper(II) sulfate crystallize outside a glass vial?
I'm making copper sulfate crystals in glasses. Within a few weeks, the copper sulfate seems to crystallize both inside and outside the glass:
(A few weeks after making a new solution)
(Yet another ...
- 17.5k
5
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0
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78
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Does catechol give Tollens’ test?
Do hydroquinones like catechol or p-hydroxyphenol give Tollens’ test?
I know that β-diketones can reduce Tollens’ reagent to give a “silver mirror”, so I would guess that due to tautomerization ...
- 38.4k
5
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223
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Splitting of atomic orbitals due to Stark effect
I am performing graduate level research on ZEKE Photoelectron Spectroscopy and central to this form of spectroscopy is Rydberg states and the Stark effect. The Stark effect is caused by an electric ...
- 71.6k
5
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187
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What pH value of 1M sodium crotonate solution supposed to be?
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ ...
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196
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Explanation of Specific Chemical Shifts on an H-NMR Spectrum
Recently, I've been looking into chemical shifts on H-NMR Spectrums and I came across a graph I didn't quite understand...
As you can see from the spectrum attached, the signal emitted from the ...
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5
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0
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793
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Solubility of PbSO4
The solubility of $\ce{PbSO4(s)}$ increase with the addition of $\ce{H2SO4}.$ Why?
I don't quite understand this. When dissolving $\ce{PbSO4(s)}$ we get the equilibrium equation:
$$\ce{PbSO4(s) <=...
- 38.4k
5
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0
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159
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Where is my antimony going?
I work in a trace metals laboratory operating an ICP-OES. I've been having some trouble with the recovery of antimony in a weak $\ce{HCl}$ solution post-digestion.
The antimony is part of a mix of ...
- 17.6k
4
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0
answers
99
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I can't understand a fragment in the Mass-Spectrum of Benzophenone
Summary:
Took multiple Mass spectra of Benzophenone; There always is a peak at $\pu{152.2}$ that I don't understand.
I made some Measurements of Benzophenone with a GC-MS. Always using EI (electron ...
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4
votes
1
answer
234
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How does a silver chloride electrode (Ag/AgCl) convert the potential in aqueous solution to the wire?
I am aware of the redox chemistry that happens at the electrode surface, but I'm not sure how exactly a change in electrical potential in the solution would change the potential in the electrode?
CommunityBot
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4
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0
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86
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Notation for spectral density in experimental community
In an open quantum system setup where the system is coupled to infinite harmonic oscillators as bath (as in the Caldeira leggett model, for example), through the Hamiltonian,
$$H = \frac{\hat{p}^2}{2m}...
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4
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1
answer
366
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Variation of conductance of saturated aqueous solution with temperature
The following question was asked in JEE Mains 2020:
Let $C_{\ce{NaCl}}$ and $C_{\ce{BaSO4}}$ be the conductances (in S) measured for saturated aqueous solutions of $\ce{NaCl}$ and $\ce{BaSO4}$, ...
CommunityBot
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