Questions tagged [recrystallization]
For questions related to dissolving and subsequently precipitating as substance. The purpose may be for purifying, creating polymorphs, or other reasons.
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Determining the chemicals in potash and crystallizing them
I have made potash by leaching wood ash in water. The potash in solution has a high pH indicating it is alkaline, and reacts with acetic and citric acid. Is there an easy way to determine the ...
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Solvent for recrystallization of benzoic acid?
Which is best solvent for recrystallization of benzoic acid?
Water
$\ce{CH3Cl}$
$\ce{CCl3COOH}$
$\pu{0.1 M}\ \ce{NaOH}$
I understand the solute/solvent should be soluble at high temperature, and ...
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Why is the solid product washed with ice-cold solvent during in the last stages of recrystallisation?
Why is the solid product washed with ice-cold solvent during in the last stages of recrystallisation? Is this to remove soluble impurities? (for example) Well, what if the impurities were also ...
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Why is the addition of methanol during the prepartion of the liquid crystal cholesteryl benzoate necesary
Here's one way to prepare cholesteryl benzoate crystals:
Step 1 Dissolve 1.0 g of cholesterol in 3 cm3
of pyridine in a conical flask.
Step 2 Add 0.40 cm3
of benzoyl chloride.
Step 3 Heat the ...
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Recrystallization Process Questions [closed]
Should a crude compound should be dissolved completely in cold solvent and then heated up?
I think non-polar solvents are best choice for recrystallization of polar compounds, no?
Recrystallized ...
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DSC Metal hysteresis (melt/cryst)
So we were analyzing Polymers using DSC and calibrated the system using Indium. I expected it to be a single transition only as Indium only has 1 known crystal structure and as I never worked with DSC ...
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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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How do native sulfur crystals form?
I was visiting an elements exhibition in the Ulster Museum (Northern Ireland) and there were these native sulfur crystals on display.
My question is how do sulfur crystals like these form in nature? ...
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Is it correct to say that SOME iodine undergoes sublimation at 1 ATM
The triple point of Iodine occurs at 0.12 atm and at standard temperature it is a solid on the phase diagram.
I understand that therefore, when heating iodine at 1 atm, it (at least some of it) will ...
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What are disadvantages of using sublimation vs. recrystallization as a method of purification?
I can only think that a small sample can be sublimed while a bigger sample size can be recrystallized. Are there more?
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Making big crystals of oxalic acid crystals from powder [closed]
How to transform oxalic acid small crystals into large crystals?
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Sublimation and recrystallization of caffeine
I'm looking to do an extraction of caffeine from energy drinks. I want to use both sublimation and recrystallization in my experiment for advanced purity.
My question is which should happen first, ...
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What is the difference between hexanes and petroleum ether
I'm trying to use hexanes as the nonsolubilizing recrystallization solvent in a multisolvent recrystallization (benzene is the solubilizing solvent) that requires an oxygen free atmosphere and hexanes ...
user9974
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Why are 'table salt and sugar are both terrible candidates for recrystallization'?
I received a comment on one of my other chemistry questions stating that
table salt and sugar are both terrible candidates for recrystallization, albeit for different reasons.
Why are salt and ...
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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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Calculating the theoretical percent purity of a recrystallization
The sample contains some percent A and some percent B with A being the majority. The solubility for both is given at two different temperatures. One where both are very soluble and one where both are ...
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Potassium Alum Crystals
This is a question regarding the crystallization of $\ce{KAl(SO4)2 . 12 H2O}$. I have an idea of what to do (I'll explain later in the explanation), but I would like to hear other suggestions encase ...
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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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Crystallization Process
In my lab, my teacher asked me to not cover the beaker or crucible during the crystallization process of different solutions (e.g, FeSO4, NaCl etc). But on the internet, on Youtube, I've come across ...
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Why do we scratch the walls of test tube in test for magnesium or calcium basic radicals?
In test for calcium ion, we add ammonium carbonate in presence of ammonium hydroxide and then white precipitate (of $\ce{CaCO3}$) is formed which is dissolved in acetic acid and then reacted with ...
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Would a melted crystal recrystallize back into the same lattice structure when frozen?
Two things that I'm not sure about melted crystals:
For a material that has only one possible crystal structure, would freezing cause it to recrystallize, or could it become amorphous upon freezing?
...
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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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Growing crystals that are in a magnetic field or subjected to an electric field
I know different crystals resonant at different frequencies but is it possible to grow crystal at a certain frequency. An example would be growing crystals using Epsom salt or Alum in a magnetic ...
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Tips for maximizing yield, purity and crystal size during recrystallization
I have already asked a similar question on titrations before. In a few months, I have a test on chemical synthesis. It is marked on the percentage yield, purity and crystal size of the product. I do ...
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Clarification on Recrystallization concept
Any help you could provide me would be greatly appreciated and I thank you for reading (even if you don't comment)
I am in an organic laboratory and as a 3rd chemistry major these concepts usually ...
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Crystallization issue
For solid-liquid mixtures, cooling crystallization process can be used to separate the solute substances from each other. Assume that we have two salts that have very close solubility in a certain ...
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Saturation of multiple solutes
Can a liquid which is saturated with a single solute, dissolve a different solute, or is saturation a universal thing? I ask because I’ve seen that different solutes have different points (amounts) at ...
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Prevent crystal growth by adding a chemical to a solution?
If I have a solution of dissolved $\ce{NaCl}$ or sugar (or some other ionic compound), is there a chemical I could add to it that would prevent crystal growth if I boil it down? I'm looking for it to ...
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How to recrystallize boric acid into flakes?
I am putting 100 g of boric acid, 400 g of water and trying to crystallize at low temperature and letting cool slowly, however it recrystallizes as needle like texture. I need soft large crystals like ...
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What would be the most suitable solvent for a single-solvent recrystallization?
The compound in question is acetanilide, and
the solvents in question are: water, ethanol, and ethyl acetate
I was thinking all three would be suitable since upon experimentation, acetanilide ...
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Recrystallization and purification techniques for getting a pure sample
Could someone explain in detail as to why exactly recrystallization gives a more pure solid sample? As well as why is would be better 'technique' to allow for the crystal to form slowly?
I was ...
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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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Best solvent for crystallization + mass recovered from crystallization + purity of the product
I have a chemistry final tomorrow and this question on my sample exam through me for a loop. I'm not entirely confident I can work out problems B and C, but those questions rely on the answer to A.
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Why polymorphs form?
We always hear about the different arrangements of molecules that lead to the formation of polymorphs, my question here is why would a polymorph form in the first place? The material was given enough ...
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Crystallization of solutions and liquids
The process of crystallization of a liquid or any solute occurs when its concentration exceeds the maximum concentration which the solvent can carry or when the temperature drops below the freezing ...
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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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Is it possible to separate salt from food, or at least convert it into something that doesn't taste salty?
A couple months ago, one of my room mates accidentally used a cup of salt to make apple crumble. She asked if there was any way to separate it, probably because I had recently reduced the acidity of a ...
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What is the correct name for this lab technique in crystallization?
Take a glass rod and rub vigorously the wall of the flask, the substance will crystallize out of the solution.
Take a fire polished stirring rod and etch (scratch) the glass of your beaker. The small ...
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Are there any general rules for choosing solvents for recrystallization?
Re-crystallization 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 ...
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