Unanswered Questions
319 questions with no upvoted or accepted answers
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Which potentials are suitable for molecular dynamics simulation of simple explicit solvents?
Which potentials (force fields) are suitable for adequately simulating (mixtures of) explicit solvents? Interesting rheological properties include viscosity, surface tension, heat capacity.
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Cobalt Chloride in various solvent/water mixtures - tested
In a recent post the solvatochromic behaviour of cobalt chloride in acetone was discussed. There were some ideas how the acetone might influence the ratio between the blue $\ce{[CoCl4]^2-}$ and the ...
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209
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Are all humectants sticky?
While using a topical lotion based on ethanol, water and propylene glycol, I noticed that it becomes sticky while drying. Propylene glycol is a humectant and is used for this purpose in ...
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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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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 ...
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154
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Dissolving ability of octane vs nonane on neoprene
I have been working with straight chain octane and nonane. The neoprene seals in some parts of the apparatus are allegedly far more vulnerable to the deleterious effects of octane than nonane - why? [...
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How to dissolve a strong resin in difficult situation?
The resin is made up from two components:
Component A: silicic acid, sodium salt (less than 10% sodium silicate)
Component B: Diphenylmethane-4,4'-Diisocyanate, isomers and homologs (MDI,Polymer-MDI)...
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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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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:
$$\ce{PbSO4(s) <=...
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159
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Where is my antimony going?
I work in a trace metals laboratory operating an ICP-OES. I've been having some trouble with the recovery of antimony in a weak $\ce{HCl}$ solution post-digestion.
The antimony is part of a mix of ...
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4
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Speed of unmixing between polar and nonpolar solvent
I have put water and silicone oil (viscosity 100 cSt) together into a jar. Then I colored the water blue to make identifying the interfaces easier. When I shake it heavily, a kind of silicone+water &...
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How does a silver chloride electrode (Ag/AgCl) convert the potential in aqueous solution to the wire?
I am aware of the redox chemistry that happens at the electrode surface, but I'm not sure how exactly a change in electrical potential in the solution would change the potential in the electrode?
CommunityBot
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Notation for spectral density in experimental community
In an open quantum system setup where the system is coupled to infinite harmonic oscillators as bath (as in the Caldeira leggett model, for example), through the Hamiltonian,
$$H = \frac{\hat{p}^2}{2m}...
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1
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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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2-Iodoxybenzoic acid oxidation reaction
I was thinking about using 2-Iodoxybenzoic acid to selectively oxidize primary alcohols to aldehydes. I've found papers using various solvents like acetone/water mixture1, 2-methyl-2-propanol2, DMSO ...
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4
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"Nivea Sun protect & refresh" melted my tub
I stupidly applied spray sunscreen on my children inside our white, acrylic bathtub and the floor ended up with a white, very sticky residue that rubs off on things, but will not wash away with ...
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Covering conformers in a molecular modelling; consider them as a static entity or work with modelling shifts as well?
I am currently working with a molecular docking project, examining potential affinities of a solvent on a protein in an assay to evaluate potential error margin. The solvent is cyclohexanol (referred ...
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278
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What is a good solvent for pentacene?
I am doing an experiment with pentacene molecule ($\ce{C22H14}$). I want to clean my sample reservoir after using it.
But I show in some literature that it is slightly soluble in organic solvent. ...
4
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254
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Why does viscosity decrease when divalent cations are dissolved into aqueous solutions of sodium carboxymethylcellulose?
Sodium Carboxymethylcellulose (CMC/NaCMC/Aqualon) is a common product used in many instances for its unique properties, especially its ability to make solutions viscous. It is well known that the ...
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Expedient phosponium synthesis (for Wittig)
I have been making ethyltriphenylphosphonium bromide (somewhat of a time crunch, would have used iodoethane instead of bromoethane if we didn't have to wait for it). All the syntheses I see of Wittig ...
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How to break down soap and detergents?
I am building a greywater harvesting system. It is a 3-stage system:
The 1st stage breaks down soap and detergents.
The 2nd stage filters the water.
The 3rd stage pumps water out of system.
What ...
4
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1
answer
71
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Is it possible to have an anhydrous solvent for virology, specifically in vitro phage assembly?
Typical protocols for lambda phage in vitro assembly call for you to dump all your viral components and buffer solutions into water. Water is a great solvent, drives extraction of energy from atp, and ...
CommunityBot
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3
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1
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Experiment on pH vs Rate of Electrolysis - what do the results actually say?
My experimental setup looks at using different pH solutions (of $\ce{H2SO4}$ and $\ce{NaOH}$) for electrolysis of water with a Hoffman setup and then measuring the rate of production of gas (note this ...
CommunityBot
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answers
66
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What could be the origin of a persisting distorted water NMR signal?
I am currently running some solvent suppression experiment on water samples. I first run a one scan 1H experiment to get the ''O1P'' and then implement it in the solvent suppression experiment (''...
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121
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Why does column chromatography not work like it's supposed to?
I'm a few months into working in an organic synthesis lab and I consider myself to have a solid intuition for, well, how chemistry works. I have ran at least 50 columns at this point but no matter ...
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277
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Use of boron(III) oxide for drying acetone
Acetone undergoes aldol self-condensation in the presence of acids or bases:
which makes drying agents such as 3A/4A molecular sieves, barium oxide, potassium hydroxide and carbonate (basic), copper(...
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Maintaining our supersaturated oceans
Supersaturates solutions can be unstable and decay beautifully once a seed crystal is introduced.
Our oceans near the surface are supersaturated with respect to calcium carbonate. This map shows the ...
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58
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Why do different products form when alkali halide reacts with zinc in polar protic and aprotic solvents?
Let's take an alkali halide such as $\ce{CH3CH2Cl}$ the two reactions in polar protic and aprotic solvents are as follows:
$$
\begin{align}
\ce{CH3CH2Cl &->[Zn, CH3OH] CH3CH3}\tag{R1} \\
\ce{...
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In solvent extraction from plant cells, what is the static organic solvent film formed?
I am researching the mechanisms behind solvent extraction of oil from microalgal cells, and it is stated in one paper that in the process of transferring the lipid out of the cell, the solvent-lipid ...
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How can the activity of ions be more than 1 if the activity of water is 1?
Now, I am quoting Chemlibretexts when they give the activity coefficient of $\ce{LiCl}$ to be $\pu{1.026}$ at the molality of $\pu{2.5 mol kg-1}$
For simplicity, assuming this is aqueous, I'll just ...
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191
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Can there be an aqueous solution with a convex meniscus?
This question is motivated by a quote from a TV show:
A detective is looking at a small vial (really a glass tube) that supposedly contains poison. Then the detective says:
You don't have to take AP ...
- 131
3
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1k
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Number of moles of acidified potassium dichromate required to liberate 6 moles of iodine from an aqueous solution of iodate ions
I came across this question in a recent exam I had taken:
How many moles of acidified $\ce{K2Cr2O7}$ is required to liberate 6 moles of $\ce{I2}$ from an aqueous solution of $\ce{I-}$ ?
So this is ...
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497
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The most convenient process to purify Oxalic Acid up to a high level of purity
I am set out to purify a batch of commercial oxalic acid with the aim in mind to end up with a highly pure product (starting from $\pu{4,000 ppm}$ total impurities and doing so with basic lab ...
3
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116
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Molar ratios not leading to complete reaction in Schweizer's reagent production
In my home lab, I've reacted $\ce{Cu(OH)2}$ with aqueous ammonia to produce Schweizer's reagent. However, I'm surprised by the amount of ammonia required to react with this amount of $\ce{Cu(OH)2}$. ...
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495
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Acetic Acid type of solvent
I want to ask a question about polar/non-polar (a)protic solvents.
The following information was given to me in the lecture hall today regarding solvents in organic chemistry.
I recall the ...
- 1,230
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708
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What pH indicators are commonly used for non-polar medium?
Compounds, commonly used as pH-indicators, are soluble in aqueous media and polar solvents (DMSO, DMF, NMP etc.) and are functional pretty much across all these solvents. However, practically none ...
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Removing Tungsten Trioxide from Tungsten Electrode
I need a very sharp tungsten electrode, and I think radial electrochemical etching with sodium hydroxide is the way to go. The problem therein (I think) is that the etching will cause an oxide layer ...
- 38.4k
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Calculating total volume mixing NaCl and water
I'm (as a non chemist) trying to calculate the the volume of a NaCl solution. The problem is that I know the volume of water prior to mixing in NaCl, but I want to know the volume of the solution ...
- 3,316
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160
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Chemistry Behind TMOS Aerogel
I have found out how to make silica aerogel.
Currently, the solution that I need to create to make the gel requires tetramethyl orthosilicate or TMOS. Furthermore, the procedure requires me to make ...
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342
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Hydrogen Peroxide Heat of Dilution
Based on some data here, I am getting the heat of dilution of 100% $\ce{H2O2}$ as approx. 1100 cal/mole.
That's about 4.6 kJ/mol if I did my math right.
Is this a correct value? Seems too low to ...
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84
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Can the directionality of an SN2 reaction depend on solvent polarity?
Because of the effects of solvation, halide ions have differing nucleophilicity in protic solvents vs aprotic solvents, iodide being the best nucleophile in protic solvents and fluoride being best in ...
- 71.6k
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110
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Poor aqueous solubility of chloroazodin
Below is the structure of chloroazodin:
Why is chloroazodin poorly soluble in water? It has multiple amine and imine nitrogens, all of which appear to be available for hydrogen bonding, and thus it ...
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391
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Solvent for Norland Optical Adhesive
I'd like to know if there is any solvent that dissolves Norland Optical Adhesive 65 (and Rhodamine 6G), but does not dissolve PMMA that is used in e-beam lithography.
I've tried acetone, methanol, ...
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3
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Why anhydrous acetic acid is differentiating solvent?
Anhydrous acetic acid is differentiating solvent in which strong acids show different strength but water isn't. Why anhydrous acetic acid shows the strength of acids clearly, but water solvent cannot ...
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Can a brine water electrolysis be looped?
Electrolysis of brine yields hydrogen and chlorine gases and aqueous $\ce{NaOH}$. So is it possible to combine the gases to form $\ce{HCl}$ gas, and mix it back with the aqueous $\ce{NaOH}$, so it ...
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290
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If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium?
If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium?
Can the same argument be applied to nitrous acid and nitrite ion in ...
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29
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Solubilizing ability of dichlorobenzenes
I am trying to understand why 1,2- and 1,3-dichlorobenzenes are such good solvents, able to solvate many organic compounds known to be hard to get dissolved.
Any precise answer?
It has something to ...
CommunityBot
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633
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The Health Effects of Alkaline Ionized Water?
I came across alkaline ionized water as my aunts bought a system called Kangen Water from Enagic Inc. The water produced by this system is claimed to contain smaller water clusters (4-6 molecules) ...
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How do I calculate the viscosity of a mixture of toluene and isopropanol?
I am trying to understand why my nanoparticles will only electrophoretically deposit in a non-polar solvent and a non-polar/polar solvent mix but not in the polar solvent. I am hoping to use zeta ...
CommunityBot
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Can a diamond dissolve in molten iron?
The melting point of diamond is 4000C and the melting point of iron is 1538C. However, the question is if a diamond is soluble in an iron solvent. Diamond is made up of carbons. And I know steel is ...
