The process of rendering something pure, clean of foreign or undesired elements.

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Chlorination of Water

Does passing chlorine gas through water form hydrochloric acid or bleach? Also, will a mixture of hydrogen and chlorine gas from electrolysis of brine do the same?
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How to obtain pure aniline from a mixture of phenol and aniline?

There is a mixture of aniline and phenol. I need to obtain (just the procedure) pure aniline. So I think the mixture should heat with Zn powder(to convert phenol to benzene) and then I thought to ...
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How to crystallize out reaction mixture from DMF?

Reaction was carried out in DMF, and TLC shows that the reaction has completed. But how to separate reaction mixture i.e. product from DMF? Edit Steglich Esterification was carried out and the ...
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45 views

Solar still and how it works

I use a solar still that holds 182 cubic feet of water. Here is how it works: There is an insulator on both sides of the metal bowl. On the outside it covers the whole thing. on the inside it covers ...
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60 views

Recrystallization of two unknown compounds?

I managed to separate a binary mixture(in solid form) of two unknown substances into two individual solid compounds. For the separation, I used an acid-base extraction with dichloromethane, NaOH, and ...
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48 views

What is a good way for a laymen to purify alcohol to near 200 proof?

I'm making herbal and medicinal mushroom tinctures and extracts. Normally I'll use everclear but it isn't cheap and 95% alcohol. Also I don't know what that other 5% is. Is it just water? Is ...
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51 views

Different techniques of distillations

I know that fractional distillation is used to separate two liquids that are miscible in one another and have close boiling points. However, I am really confused about vacuum and steam distillation - ...
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78 views

Impurities in Sulphuric Acid drain cleaner

I have been wanting to do a bit of amateur chemistry and since sulphuric acid is such a useful and ubiquitous reagent I need to get hold of some. Since ordering it from eBay is expensive (postage and ...
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27 views

The proteins “eluted” or “were eluted”?

In describing proteins, I've written "the proteins detached from the [Ni-IDA] matrix and were eluted from the column" Should I use "were" or can something simply "elute" ?
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Why is my Aqua Regia solution not reacting properly?

I mixed up a batch of Aqua Regia to purify gold mixed in among small amount of other metals. I dissolved the metals in the typical 1:3 $\ce{HNO4}$ - $\ce{HCl}$ ratio. But, I forgot to neutralize the ...
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304 views

How to make artificial sea water

My 7th grader is embarking on a long-term science project and I'm on tap to "help." He is showing a strong interest into finding ways to get drinking water to the masses. His idea is that we need to ...
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78 views

Best place to take off vacuum for distillation

I have seen vacuum take-off adapters that are essentially plugs, which could be placed at the top of a three-way above the fractionating column, and also straight and bent vacuum take-offs with an ...
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228 views

Does caffeine isolated from coffee contain harmane?

I'm not sure whether the caffeine contained in otc caffeine pills is made synthetically or isolated from coffee and other plants, but if the latter is the case, is it likely that it contains the ...
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Azeotropes and separation by distillation?

I have just recently learnt the theory of fractional and normal distillations and the basics of maximum and minimum boiling azeotropes. Most books say that the components of the mixture forming an ...
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4k views

How does alum help 'clean' water?

How does the addition of alum — potassium aluminium sulfate or $\ce{KAl(SO4)2}$ — help settle the dust particles in water? There was such a statement in my Year 9 textbook, and so I was wondering how ...
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Removing titanium from tantalum crucible

I'm trying to remove titanium filling from a tantalum crucible for a high-temperature effusion cell. I've managed to get a majority of the material out with tweezers, but some remains and is ...
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220 views

Is it safe to condense water into a liquid nitrogen trap?

I'm trying to remove water from an imidazolium salt (i.e. dry the salt). However I want to know if it is safe to remove the water under vacuum. Is it safe to condense water into a liquid nitrogen ...
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How are pure substances (elements, compounds, etc) produced?

How are large quantities of the substances we use in the lab generally produced? (As in the process from getting the stuff out of the ground to use in the lab) How 'pure' are they? Also: is it ...
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Crystallization from a solution

I was wondering if there is any other way to crystallize materials from a solution other than using supersaturation? Thanks,
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What is the process for purifying KOH?

I'm partnered with a jewelry production company whose plating baths require KOH. We're located in Indonesia, where import fees are absurdly high, and reliable suppliers are rare. A local shop sells ...
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Acetic acid freezing distilation

How can acetic acid be distilled by freezing when its freezing point is above the freezing point of water. Examples on the web show the water portion of the vinegar as ice and the acid as a liquid ...
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210 views

What happens during cleaning silverware?

I know two distinct recipes for cleaning silver: Put them into a pot with some club soda and a piece of aluminium foil and pour over a hot water. Gently clean silverware with a fine chalk powder ...
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299 views

Isolating salt from sea water using filters

Could a filter be used to isolating salt from sea water? Could we say that the water molecules are smaller than the molecules of salt dissolved in the water. I have no relation to chemistry or ...
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2k views

Copper Chloride: neutralizing and disposal

I plan on etching some PCBs with hydrochloric acid and hydrogen peroxide, which will therefore produce some kind of copper chloride (green color) which is highly toxic if released into the ...
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Difference between lab-grade and food-grade purity?

What is the difference in purity betwen lab-grade and food-grade when talking about potentially consumable compounds? As an example let's take ascorbic acid powder: if it's marked as lab-grade, does ...
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104 views

Negative retention for chloride in hydrolysate filtration

I tried to fractionate proteins as a function of their size with an ultrafiltration membrane. I observed a higher concentration of chloride in my permeate than in my feed or retentate. The proteins do ...
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318 views

What is the behavior of a Zwitterion during ion exchange chromatography?

We're interested in purifying a protein that has an azide moiety using ion exchange chromatography. Due to its unique structure, the moiety is a Zwitterion with a novel chemical behavior. My question ...
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Silver, its bactericidal features and water

I often hear that water gets purified by being in a silver vessel, which sounds plausible because of bactericidal feature of silver. What doesn't sound plausible, though, is the way it's explained: ...
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Are there any general rules for choosing solvents for recrystallization?

Recrystallization is a nice way of purifying a product, but choosing a suitable solvent if you can't rely on the literature seems like a lot of trial-and-error. Are there any general rules on which ...
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How does Polytetrafluoroethylene (Teflon) differ from Polyvinylidene fluoride (PVDF) as a protein binding membrane material?

PTFE and PVDF (durapore) are both used in protein binding filter membranes (Millipore specifically). Chemically speaking the two polymers differ quite significantly due to the additional fluorides and ...