Related audio. Denatonium benzoate. Book club — Deep Sniff by Adam Zmith. Magnesium sulfate. Brian Clegg explains how bath salts may actually be more than just relaxing. Meera Senthilingam This week, we head to the UK countryside for some healing.
Taking us there is Brian Clegg Brian Clegg The town of Epsom, in the English county Surrey, is probably best known for its racecourse, but it is also a town with mineral springs and gave its name to a particular substance extracted from them, known as Epsom salts.
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Load more articles. No comments yet. You're not signed in. Flash Chromatography Flash chromatography is a purification method used to separate mixtures. In the bottom of the burrett, add 1cm steel wool and 1cm sand on top of the steel wool 2.
Add silica gel silica with a little ethyl acetate to fill half of the column 3. Pour 1 cm more sand on top silica 4. Load compound dissolved in as little organic solvent as possible 5.
Collect vials of product and run TLC of vials to determine if a product is present 7. After both products have stopped showing up on TLC plates, flush out silica and keep vials separated, run NMR or IR for classification of the pure products. Add some amount of the powdered hydrated salt in the crucible, and measure it's total mass with the lid.
My first instinct would be to question how well you heated the material and under what conditions. Insufficient heating would mean that you might still have water remaining in the material.
Anhydrous, powdered magnesium sulfate will absorb water relatively quickly at ambient conditions, though it will depend on the temperature of the solid, how anhydrous it is and the humidity of the air.
Something more to consider is that the crystalline form will absorb water at a slower rate. Were you dealing with powder or crystals? Unfortunately, it isn't possible to judge the kinetics without more information. Perhaps you can provide your procedure? Sign up to join this community. The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. How fast does MgSO4 absorb water from the air? Dry blue Wet wet. It works well in solvents like diethyl ether, but not as well for ethyl acetate. It is a fast drying agent, in part because it comes as a fine powder with a large surface area. It is very efficient in ethereal solutions, but it also absorbs other polar compounds like alcohols, etc.
In addition, it is slower compared to magnesium sulfate, etc. They cannot be used to dry acidic compounds since they react with them. Both have a very high capacity.
Sulfuric acid forms hydrates while phosphorous pentoxide is ultimately converted into phosphoric acid. One of the main problems in the drying process is that the equilibrium above is shifted to the left if the mixture is heated increase in entropy! Therefore, the drying agent has to be removed by filtration or decanting from the dry solution prior to removal of the solvent.
Drying agents like Drierite or molecular sieves can be recycled several times by heating them to an appropriate temperature see above. Example: Reversibility of drying process The following data can be obtained from the literature:. The solution often times warms up a little bit when the drying agent is added. Practical Aspects for the Use of Conventional Drying Agents One of the main problems is that many drying agents do not only absorb water, but also other polar compounds.
Hence, an excess of drying agent should be avoided in order to prevent the absorption of the target compound, particularly if the compound was polar as well. Even though water usually has a higher affinity towards the drying agent, excess can also lead to significant loss of product. Note that the presence of other polar compounds i. How do I know that I added enough drying agent? Before a drying agent is added, the organic layer has to be separated as thoroughly as possible from the aqueous layer.
It does make very little sense to add the drying agent if there is a second layer on the bottom or the top depending which organic solvent is used.
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