Questions tagged [separation-techniques]

For questions about the separation of mixtures and solutions into pure compounds

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How to separate isotopes [closed]

I've searched a bit about this, and all methods are basically based on the atomic weights: There are three types of isotope separation techniques: Those based directly on the atomic weight of the ...
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Calculation of the Seperation factor of Ethanol / Water rectification based on two saturated vapor temperatures

I want to calculate the efficacy of a Water / Ethanol rectification based on two temperatures with help of a vapor-liquid equilibration diagram. The first temperature is measured right above the ...
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Why does a big protein move during gel electrophoresis but to a lesses extent through a size exclusion column?

A big protein going through gel electrophoresis will be forced through the gel, it will drift a small way and will show on the top of the gel, while in size exclusion, the big protein is not forced to ...
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How to remove oil/grease contaminant from an aqueous solution?

I have a solution of water and calcium nitrate that is contaminated with some sort of heavy petroleum oil, semi-solid at room temperature a bit like petroleum jelly, and a strong odor of very crude ...
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What solvent dissolves calcium nitrate but not ammonium nitrate?

I am experimenting with a precipitation reaction between ammonium sulfate solution and calcium nitrate. Calcium sulfate precipitates and can be filtered out easily. I am wondering if there's a way I ...
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1 answer
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Separation methods [closed]

I put some iron nails in water, and obviously, those started oxidizing, making those hydrogen bubbles. Some days after, the water was orange, indicated that the FeO has just dissolved in it. I found ...
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My particles won’t separate without neutralizing the solution. I want to understand why?

I etched active carbon with a concentrated KOH solution and added HCl to neutralize the KOH. Separeted the particles with centrifuge at 4000 rpm. They should be micron sized. My boss asked me to stop ...
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How does a freeze-thaw cycle separate a mixture?

Imagine that I defrost a tube of serum (only the yellow stuff, with blood cells removed) standing still and upright in ambient air. I have seen that as it defrosts the sample separates into different ...
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2 votes
1 answer
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Why can I extract all metabolites from blood plasma with one solvent, but to extract only fatty acids I must use many solvents?

I want to do a metabolite study using GC- without derivatization and UPLC-MS (RP and NP) on samples of plasma and urine. My hypothesis is agnostic about which metabolite will correlate with the ...
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1 vote
1 answer
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How do I separate an Indium-Gallium alloy into Indium and Gallium?

I've recently learned more about Indium and Gallium, and I find them quite interesting, especially how an alloy can be manually made simply by rubbing them together. I'm curious though, is there a ...
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Has anyone added dyes to a mixture about to separated by chromatography in order to visualize where the desired product lies?

Usually in preparative chromatography one needs to know when the desired substance to be separated is coming down the pike. Often this required some sophisticated instrumentation. But, it occurred to ...
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How to adjust selectivity of gas-permeable PDMS membranes for environmental applications?

I have an idea about making an environmental sensor that uses a gas-permeable membrane (GMP) and how its probe could be submerged in a water source with an off the shelf gas sensor. So far, my ...
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1 answer
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What is the function of thin layer in thin layer chromatography?

I just learned about the thin layer chromatography, which I think is basically the same as the paper chromatography. I am wondering what is the function of the thin layer? I mean, what's special about ...
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How to separate manganese(IV) oxide and chromium(III) hydroxide?

I am trying to find a reagent that keeps either $\ce{MnO2}$ or $\ce{Cr(OH)3}$ solid and make other soluble so I can centrifuge or use filtration. I thought of $\ce{NaOH},$ but I could not find any ...
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Why are cations detected in capillary gel electrophoresis with a positive applied voltage and a coated fused silica capillary?

In capillary gel electrophoresis, when a positive voltage is applied to a coated fused silica capillary, why are positively charged ions (among positive, negative and neutral) detected first? What is ...
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How are Silanol groups functionalized unto mesoporous silica structures?

As described in this research paper: Immobilization of Jacobsen type catalysts on modified silica, Jairo Cubillos , Edwing Grajales, Santiago Vásquez, Consuelo Montes de Correa, Rev. Fac. Ing. Univ. ...
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How do I get calcium citrate to precipitate in experiment on extraction of citric acid from juice?

I was planning to extract citric acid from mango juice by first using Aspergillus niger fungus by fermentation to convert the mango juice to citric acid, then extracting by first adding sodium ...
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7 votes
2 answers
949 views

How to separate Cu and Ni from alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn < 5%)?

I have an alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn, Ag, Si in small amount < 5%). How can I separate Cu and Ni from this alloy? I tried to dissolve alloy in sulfuric acid, ...
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Which process would separate the mixture of toluene, cyclohexane and water?

I think that answer would be: Toluene and cyclohexane do not dissolve in water (since they are nonpolar), so I would first separate the water from the mixture with a separator funnel. A mixture of ...
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1 answer
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Chromatography- why tM is separated from other peaks? [closed]

tM in Chromatography is the time of exist mobile phase. But, the mobile phase exist together with all the compunds that tasted in the process. So, why in the graph of signal to time we can see a peak ...
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Dynamic viscosity of gas mixture (appropriate estimation)

What estimation of the dynamic viscosity $\eta = f(T)$ $([\eta] = \pu{Pa·s})$ of the gas mixture components would you recommend during adsorption at a low temperature, approx. $\pu{293 K}$ to $\pu{333 ...
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are refractometers generic?

I need to check the presence (and also purity approx) of a substance in solution. I have a very good reference (10mg/1ml - the substance in water). Can I use a refractometer to do this? I am trying to ...
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how to separate a mixture of sodium chloride and sodium hydroxide

I recently did an double displacement reaction in that I have formed a solution of water with sodium hydroxide and sodium chloride are dissolved in it. now I want to separate both of them
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How to make acetic acid more volatile so that it can be removed by vigorous aeration of an acetic acid-water mixture? [closed]

I want to remove acetic acid from a mixture of acetic acid and water by aeration. The concentration of acetic acid is 200 ppm (mg/L). The pH of the water is more than 5. I want to reduce the acetic ...
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527 views

Purification of Red Phosphorus

The Boring Stuff I'm well acquainted with various fields of science & engineering, but my foray into the world of chemistry is relatively recent. I'm in a location (probably most of us are to some ...
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Solubility Product, and it's relation to solubility

In order to remove temporary hardness of water, it is boiled. On boiling, while Ca(HCO3)2 gives CaCo3(ppt.) , Mg(HCO3)2 gives Mg(OH)2(ppt.). According to my book precipitation of Mg(OH)2 occurs due to ...
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Ways to determine the concentration of alkyl halides in organic solvents

I have a volatile alkenyl bromide dissolved in hexanes. I have to use the halide in a Grignard reaction but separating it from hexanes is hard (the bromide is light sensitive and very volatile). I ...
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1 vote
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Separating sodium sulfate from chromium trioxide solution

I was looking at the industrial process for the production of chromium trioxide by treating sodium chromate or the corresponding sodium dichromate with sulfuric acid. This results in the formation of ...
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3 votes
1 answer
155 views

How do you separate microcrystalline cellulose from amino acids in a powder mixture?

I am looking to separate out the microcrystalline cellulose that has been mixed in with amino acids in a powder mixture. I have tried suspending the powder mixture in water and then filtering out the ...
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4 votes
2 answers
248 views

How much does oxygen enrichment improve some combustion engines?

This question is about how much the combustion efficiency increases with oxygen enrichment in modern combustion engine designs. A desirable way to answer is to give the fuel efficiency dependency on ...
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1 vote
1 answer
254 views

Theoretical plates in Plate theory of chromatography

In "Chromatography theory" by Scott and Cazes, The plate volume is given as ($v_m+Kv_s$) where $v_m$ and $v_s$ are the volume of stationary and mobile phase in the column and $K$ is the ...
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Distilling milligram quantities of oil like it's late 1970s

In a currently retracted* manuscript by Tomas Hudlicky [1, Retraction Watch] the following has been noted: Fifty years ago professors took an active part in all laboratory instructions and they ...
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2 votes
1 answer
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Why does HgCl2 react with HCO3^- but not with CO3^2-?

I have started learning Qualitative Salt analysis recently. When I was reading about tests to distinguish $\ce{CO3^2-}$ and $\ce{HCO3-}$, I came across a line in a book which states $\ce{HgCl2}$ ...
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What are some Qualitative test/s that you can use for benzophenone? [duplicate]

I have determined one of my unknowns to be benzophenone and in a lab setting (but that isn't possible because of COVID-19) I would conducted the 2,4 DNP test which should yield a positive result. ...
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4 votes
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How can should one separate and purify benzophenone from salicylic acid?

I am working with two solids and I know that they are benzophenone (s)(ketone) and salicylic acid (s) (carboxylic acid). I am curious to know what is/are the best method of extraction and ...
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1 vote
1 answer
144 views

How to store small amounts of gas

I need to store small amounts of gas. I already saw devices that look similar to the image below, but I don't know how they are called. Does someone here know how these devices are called? I am also ...
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3 votes
1 answer
5k views

Separating lanthanides using ion-exchange method

Following statements are on Separation of rare earth metals (lanthanides) via in-exchange method The tripositive ions are strongly sorbed by cation exchange resin: $\ce{La^{3+}}$, the largest is ...
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1 vote
2 answers
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Can separated and purified substances be obtained from a chromatogram?

I am studying chemistry, and I am learning about chromatography. But I am confused about how chromatography is used to ‘separate and purify’ substances. I have learnt about chromatography paper, ...
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-1 votes
1 answer
420 views

What is the physical property used in choosing the separation techniques for CaCO3 and KCl and NH4Cl [closed]

I've been scrolling through a chemistry past question but when I came across this I tried to solve it but it keeps confusing me
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1 answer
321 views

How to separate a racemic mixture of 1,2-diols

[upjohn dihydroxylation]2I want to ask that i synthesise R-substituted-1,2-Diol with (ee=1:1) ratio of R-, S- with the help of Upjohn Dihydroxylation. i try to seprate it by different mobile phasese ...
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-3 votes
2 answers
226 views

How would I separate a solution of sodium iodide and water in order to obtain the sodium [closed]

I am an amateur in this field of science and I am trying to separate a solution of Sodium Iodide and water. How would I separate the solution so I can obtain sodium?
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Method of separating product and conserving the catalyst

I'm looking for a way to separate reaction product of iodobenzene with ethyl 2-methyl-3-oxopentanoate in 1,4-dioxane (toluene is an alternative as a solvent). The catalyst being used is $\ce{Pd2(DBA)3}...
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10 votes
1 answer
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What is the scientific term to describe the operation of a bong?

What is the scientific term for the separation of dust particles from air by suction through a specialized flask in a way similar to the operation of a bong? The thing that led me to this was a ...
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2 votes
1 answer
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Does the distillation of alcohol cause the fractioning of isotopes and carbon-12 enrichment?

In water, distillation causes fractioning of the $\ce{^{18}O}/\ce{^{16}O}$ oxygen isotopes (Wikipedia). Does something similar happen to the $\ce{^{13}C}/\ce{^{12}C}$ and possibly $\ce{^{14}C}$ ...
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-1 votes
1 answer
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Titration/ Separating Soluble Salts/ NaHSO4

When performing titration between NaOH and H2SO4, both Na2SO4 and NaHSO4 are formed (both are soluble in water), is there any method to obtain crystals of NaHSO4? (Maybe by separating two soluble ...
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3 votes
1 answer
151 views

Do companies recover carbon dioxide and water from the purification step of cryogenic air separation, and how?

In the 3rd step of cryogenic air separation, filtered air is purified to remove water, $\ce{CO2},$ and hydrocarbons from the $\ce{N2}$-$\ce{O2}$-$\ce{Ar}$ stream. Im interested in knowing what happens ...
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3 votes
1 answer
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Separation of methanol–water mix in a plate distillation column

I conducted an experiment to separate methanol and water. I am trying to determine the mole fraction of the distillate collected but having a little trouble with the calculation. The flow rate was $\...
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2 votes
1 answer
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HPLC Columns For Compounds Not Soluble In Non- Or Low Polar Solvents [closed]

Can someone recommend HPLC columns for compounds which are not soluble in no- or low polar solvents (hexane, isopropanol, toluene, and dichloromethane)?
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coffee concentrate and water separated after 2 hours. How/why?

I'm asking because this makes no sense to me and making sure I'm not stupid. I brewed 10 gallons of cold brew concentrate(TDS 12.2) and mixed it with 10 gallons of water. I moved 10 gallons of the ...
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4 votes
1 answer
149 views

How to conveniently separate Cd impurities from ZnO without contaminating it?

How could I separate Cd impurities from ZnO without contaminating it and without using overly expensive equipment or extremely dangerous solvents? I don't want to contaminate it by introducing other ...
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