Questions tagged [recrystallization]

For questions related to dissolving and subsequently precipitating as substance. The purpose may be for purifying, creating polymorphs, or other reasons.

15 questions with no upvoted or accepted answers
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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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1answer
964 views

Why add specifically hot solvent during recrystallization procedures instead of heating it up after?

Recrystallization methods that I have seen online and in manuals involve adding a minimum amount hot solvent to the solid mixture. Is there a reason I should do this instead of adding an equivalent ...
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164 views

Could you form quartz crystals by melting and cooling sand very slowly?

Since glass is amorphous quartz and when you slow the cooling of something enough it will crystallize, couldn’t you melt $\ce{SiO2}$ (sand) and then very slowly cool it to cause spontaneous nucleation ...
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339 views

What determines the maximum size of salt crystals as grown in flux growth?

Like many other children, I grew single crystal salt crystals in a salt solution. This is a common and fun experiment for children. However, with both this experiment, and with flux growth methods ...
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0answers
103 views

What do DNA crystals look like?

I had about 5 ug DNA suspended in water, which I dried thoroughly in a vacufuge. I obtained a whitish crystal (very similar to table salt, although the structure seems uneven and it's hard to tell) ...
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21 views

Anhydrous Chromium Alum production

I recently started a small project of making home-made chromium alum crystals, as can be found on many sites, videos and recipes all around the internet. I tried calculating the amount of salt I ...
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39 views

Readings about chiral resolutions at the undergraduate level

Does anyone know of a resource which clearly explains the scientific theory and experimental methods involved in chiral resolutions? I have access to the American Chemical Society, Tetrahedron, ...
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325 views

Multi-solvent recrystallization to extract solute from glycerol?

I have compound A contaminated with impurity B. Recrystallization in water would not yield pure compound A since impurity B is less soluble in it. The only solvent in which substances A and B have ...
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0answers
48 views

Pressure/ vacuum on preciptation of a borax saturated solution

Trying to go back to my collage chem/physics. We put a supersaturated solution of borax on the stove. (heated water, added borax till it would not take more borax). Placed them under vacuum 15 inhg,...
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51 views

Non-destructive solvents for cyan-salts

What dissolves cyan-salts (NaCN and KCN) without destroying them the way water does via hydrolysis? I have to make my own cyan-salts, so they're somewhat precious to me. Every time I have to ...
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64 views

Drying sodium tetraborate for use as a standard

I am currently attempting to purify technical grade sodium tetraborate decahydrate by recrystallization for use as a titration standard. I don't have a requirement for a specific grade or purity. I'm ...
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50 views

Why does cobalt(II) chloride (CoCl2) crystal melts?

I made $\ce{CoCl2}$ crystals by making a concentrated solution. After the crystals formed I took them out of the solution for drying. After a time I noticed that they were still wet so I dried off ...
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109 views

Steps of crystallization

An excess of copper(II) oxide is added to dilute sulfuric acid to make crystals of hydrated copper(II) sulfate. The processes listed may be used to obtain crystals of hydrated copper(II) sulfate. ...
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1answer
485 views

How does recrystallization work to purify if compounds have equal solubilities, but one is present in a greater quantity?

Every article or text I've read on crystallization states that it works by taking advantage primarily of differences in solubilities, but I've also been told that it can purify compounds with ...
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30 views

Inorganic Exclusion Rate to Expect During Recrystalization?

In the following context, what approximate exclusion rate can I expect towards all combined inorganic ions (metals, ...) per recrystalization cycle? Can I expect it to radically evolve along the ...