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Topic: Separation of mixtures


In the News (Sat 22 Nov 08)

  
  Separation of mixtures and chromatography
A heterogeneous mixture of solid and liquid or solid and gas is usually fairly easy to separate because of the 2 different physical phases.
A mixture of two or more solids is usually separated by utilizing the different chemical or physical properties of the substances.
Chromatography works to separate a mixture because the components of a mixture distribute themselves differently when they are in contact with a "two phase system".
www.800mainstreet.com /e3/e3.html   (2490 words)

  
 Separation of Mixtures
Mixtures are all able to be separated by exploiting some physical property.
An example which could be separated by hand might be a dry mixture of salt and sand.
He was able to separate what had been thought to be one compound into two.
dbhs.wvusd.k12.ca.us /webdocs/Matter/SeparationOfMixtures.html   (488 words)

  
 Mixtures and Substances HomePage
Mixtures have a variable composition, since they can have different amounts of component substances, and hence their properties are variable and usually nondistinct.
Heterogeneous mixtures are mixtures in which the composition is not uniform, such as chunks of one substance mixed with another or a layer of one substance over another.
A mixture of solid particles in a liquid can be separated by pouring the mixture through a filter that traps the solid particles while the liquid passes through in a process called filtering.
ch185.semo.edu /mixtures/mixtures.html   (1055 words)

  
 Process and device for the separation of mixtures which form an azeotrope - Patent 4349416
A process and apparatus for the separation of components from a mixture which forms an azeotrope is disclosed by subjecting the mixture to extractive distillation to remove one of the components and regeneration to separate another component from the extracting agent added to the extractive distillation column.
In this process, the mixture to be separated, which forms an azeotrope, is fed into the lower part of the extractive distillation column, whilst the extracting agent is fed into the upper part of this column.
For the ethanol/water mixture preferably to be separated according to the invention, ethylene glycol, diethylene glycol or ethylene glycol methyl ether may be preferably mentioned as examples of the extracting agent, and ethylene glycol may be particularly preferably mentioned as an example of the extracting agent.
www.freepatentsonline.com /4349416.html   (3508 words)

  
 IBMEM pervaporation and vapour permeation
Pervaporation is a method for the separation of mixtures of liquids by partial vaporization through a non-porous membrane.
The separation principle governing pervaporation is mainly due to polarity differences and differs significantly from distillation which depends on differences in vapour liquid equilibrium relationships to affect a separation.
Pervaporation and vapour permeation are used for an effective and economic separation of mixtures of substances with small volatility differences (boiling point) and azeotropic mixtures.
www.pervaporation.de /international/pervaporation.htm   (191 words)

  
 GCSE Chemistry Notes on Elements, Compounds, Separation Methods of Mixtures and Chemical Equations at Doc Brown's ...
It is used on a large scale to separate the components of crude oil, because the different hydrocarbons have different boiling and condensation points (see oil).
(1) separation of sand and salt mixture or (2) salt preparations (a) from dissolving an insoluble base in an acid to form a soluble salt or (b) preparing an insoluble salt.
The mixture is put in the separating funnel with the stopper on and the tap closed and the layers left to settle out.
www.wpbschoolhouse.btinternet.co.uk /page01/ElCpdMix/EleCmdMix.htm   (6881 words)

  
 Separation Of Mixtures And Compounds For K Through 12
Separation Of Mixtures And Compounds For K Through 12 Patricia A. Riley Lincoln Park High School Viva Henson Andrew Jackson Elementary School Patricia Doyle Peck Elementary School Objectives: 1.
To separate mixtures by using such techniques as solubility differences in water, filtration and evaporation.
Repeat the electrolysis of water using a U-tube filled with a mixture of distilled water, sodium sulfate and bromothymol blue indicator.
www.iit.edu /~smile/ch9130.html   (517 words)

  
 Re: separation of mixtures
It takes a huge amount of energy to separate charged particles (like sodium and chloride in salt) and so salt is very stable.
The water (and pectin, sugars, and other polar things) passed through a filter and the grapeskins stayed on top (and so did the tannins and other nonpolar things that were inside the grapeskins that were not yet extrated by acetone).
He washed the column with a nonpolar solvent and the nonpolar things came through the column faster than the polar things (which stick to clay because it is polar).
www.madsci.org /posts/archives/oct98/907211616.Ch.r.html   (1361 words)

  
 Infobase
Mixtures are often relatively easy to separate into their components.
Sometimes it is not possible to separate the heavier particles in a mixture using the gravity method.
The spin-dryer in a washing machine is a form of centrifuge and the same method is used to separate sugar crystals from liquid sugar.
www.hi.com.au /resource/rfacts.asp?kla=1&subtopicid=1410   (354 words)

  
 Critical properties and phase separation in lattice Boltzmann fluid mixtures - Phase separation under a steady shearing ...
We observe in the top view that the phase separation pattern appears to have a "string-like" form at the boundary, but that the structure within the film is actually more complicated.
14 increases and the phase separation morphology ultimately coarsens to a state where the fluid interface lies perpendicular to the shearing planes and parallel to the flow direction.
The surface-induced "structuring" of the blend morphology would be accentuated in the early stages of phase separation if one of the blend components has a preferential attraction to the shearing boundaries.
ciks.cbt.nist.gov /~garbocz/lbseparate/node11.html   (770 words)

  
 Project MMEDS
The still is accompanied by a reboiler in which the source material is heated, a condenser in which the heated vapor is removed and condensed back to the liquid state, and a receiver in which the concentrated or purified liquid is collected (Washer 3).
It is normally the preferred method of distillation when the component to be separated has a significantly lower boiling point than the other components of the mixture, as a larger boiling point difference enhances the effect of distillation (Washer 21).
Although the effects of distillation tend to induce a single phase mixture to transform into a two phase mixture, the absence of gravity prevents the recovery of each phase separately, thus eliminating the value of distillation.
www.nmsu.edu /~flyingag/projects_ascend.html   (1025 words)

  
 find: chemistry labs about separation of mixtures
Separation processes are used to decrease the complexity of material mixtures.
Separation of mixtures can be by mechanical means, such as by weight, evaporation...
Separation Of Mixtures And Compounds For K Through 12 Patricia A. Riley Lincoln Park High...
www.audio-fonic.de /chemistry_labs_about_separation_of_mixtures.html   (223 words)

  
 CHE 131 Lab-Substances and Mixtures of Substances
In fact, the essential distinction between mixtures and "pure" substances is whether or not they can be separated by physical means.
Physical means of separation are those techniques which utilize the physical properties of a substance (e.g., melting point, solubility).
Salad dressing is a mixture with which you are familiar (basically, vinegar, oil, and spices).
web.centre.edu /che/che131_lab/mixtures.htm   (1542 words)

  
 Mixtures - School for Champions: Succeed in Physical Science   (Site not responding. Last check: )
Suspension mixtures have larger particles and are heterogeneous.
It is possible to separate the milk and cream particles (or cream globules) by spinning the liquid in a centrifuge.
A simple mixture consists of substances that do not react chemically and can be separated by mechanical means, while in a compound the substances react and combine chemically.
www.school-for-champions.com /science/chemixtures.htm   (1419 words)

  
 Molecularity: Physical and Chemical Separations
To simulate nanoscale physical and chemical separations, and to reveal the characteristics of pure substances and mixtures at the nanoscale.
At the macroscale, a mixture may be separated into its component pure substances using physical processes only, where a physical process is one that does not alter the identities of any of the components.
Stir the sand/water mixture with a stirring rod, and carefully pour mixture into the funnel until the water level is near (but not over) the top of the filter paper.
www.wpi.edu /Academics/Depts/Chemistry/Courses/General/separations.html   (1547 words)

  
 Separation of mixtures   (Site not responding. Last check: )
In chemistry, separation of mixtures is the separation of the elements of a mixture.
Distillation - used for mixtures of liquids with different boiling points, or for a solid dissolved in a liquid.
Chromatography used to separate different dyes or pigments.
www.serebella.com /encyclopedia/article-Separation_of_mixtures.html   (874 words)

  
 First page of Disc Electrophoresis 2   (Site not responding. Last check: )
Zone electrophoresis provides a comparatively innocuous method for the separation of ionic mixtures and is based on differences among the electrophoretic mobilities of the constituent ions.
In most zone techniques separation is dependent solely on the differences in the free electrophoretic mobilities among the constituent ions, and the supporting matrix, e.g., filter paper, is used primarily to reduce convection.
Thus the separation of mixtures is achieved in such a gel matrix through dimensional as well as charge differences.
www.pipeline.com /~lenornst/First_page_of_Disc_Ele2.html   (473 words)

  
 Separation of Organic Isomers - Isis Innovation Licensing Opportunity
Most isomeric mixtures are difficult to separate and normally require highly specialised techniques.
Isomeric mixtures can be separated by crystallisation and other methods but this is usually difficult due to the similar physical properties of the isomers.
The technique provides a straightforward and novel method for separating polar organic compounds, and is a useful alternative to the usual methods of chromatography or crystallisation.
www.isis-innovation.com /licensing/476.html   (304 words)

  
 Mixtures and Compounds
If we fill a piece of cellophane tubing with a mixture of starch and sugar and place it in pure water, the sugar molecules (red dots) will diffuse out into the water until equilibrium is reached; that is, until their concentration is equal on both sides of the membrane.
Link to description of exclusion chromatography, where the molecules in a mixture are separated by size.
Link to description of affinity chromatography, where molecules are separated on the basis of their attraction to material in the chromatographic column.
users.rcn.com /jkimball.ma.ultranet/BiologyPages/M/Mixtures.html   (541 words)

  
 Lycaeum > Leda > Analytical separations of mixtures of hallucinogenic drugs
A mixture of chloroform and methanol (3:1) was used as a general solvent for the pure compounds.
Ibogaine and mescaline required a catalyst, 4,5,6, trimethylchlorosilane [7] for efficient conversion, and this catalyst was used routinely for the mixed compound studies.
The advantage of the iodoplatinate spray is that, though the resulting colours are only varia-tions of brown, a spot may be scraped from the plate and reduced with sodium sulfite [9] after which the drug may be appropriately redissolved.
leda.lycaeum.org /?ID=16582   (2085 words)

  
 Chemistry - Mixtures
- heating to evaporate the water from insoluble or soluble particles in the mixture (e.g.
- separates coloured dyes by dissolving the dyes in a solvent and drawing the lighter and heavier particles along a filter paper strip
separating the lighter liquid plasma from the heavier blood cells in blood)
qldscienceteachers.tripod.com /junior/chem/mixtures.html   (387 words)

  
 Liquid-Liquid Separation
Liquid – liquid mixtures must be settled and coalesced before they can be separated.
Gravity Settlers or decanters can be either horizontal or vertical vessels designed to continuously settle, coalesce, and withdraw settled liquids.
Cyclones and centrifuges have also been used for separating liquid/liquid mixtures by enhancing the settling rate and reducing the separation time.
www.process-controls.com /techsales/Kimre_liquid_separation.htm   (176 words)

  
 Van der Waals and the Dutch School. Phase Transitions and Critical Phenomena
The phase separation of even only two-component fluid mixtures is considerably more complicated than that of pure fluids.
Phase separation of fluids is a topic of major practical interest, for instance, in the chemical and materials processing industries, as well as in geochemistry, oil and gas recovery, and metallurgy.
The thermodynamic foundation of the field was laid between 1873 en 1878 by the U.S. chemist Josiah Willard Gibbs.
www.knaw.nl /waals   (453 words)

  
 new
Most laboratory work in biology requires the use of techniques to separate the components of mixtures.
Separation of mixtures can be by mechanical means, such as by weight, evaporation or other...
A solid which has not dissolved in a liquid can be separated by filtration.
www.glasser-whitley.co.uk /separation_mixtures_techniques_chemistry_news.php   (208 words)

  
 SparkNotes: Stereoisomers: Racemic Mixtures and Enantiomeric Excess
A solution in which both enantiomers of a compound are present in equal amounts is called a racemic mixture, or racemate.
Therefore it is impossible to tell a racemic mixture apart from an achiral substance using polarimetry alone.
These techniques are also applied to mixtures of enantiomers beside racemic mixtures, for example to purify a species from small amounts of its enantiomer.
www.sparknotes.com /chemistry/organic3/stereoisomers/section2.rhtml   (778 words)

  
 UNODC - Bulletin on Narcotics - 1969 Issue 1 - 004
A study was made of the separation of mixtures of dimethyltryptamine, mescaline, psilocybin, ibogaine, and lysergic acid diethylamide, using both gas chromatography and thin-layer chromatography.
The solvent-reaction mixture was dimethylformanide, bis (trimethylsilyl) acetamide and 4,5,6, trimethylchlorosilane in the proportions 1:4:1.
The advantage of the iodoplatinate spray is that, though the resulting colours are only varia-tions of brown, a spot may be scraped from the plate and reduced with sodium sulfite [ 9] after which the drug may be appropriately redissolved.
www.unodc.org /unodc/en/bulletin/bulletin_1969-01-01_1_page005.html   (2105 words)

  
 CHM235L - Exp. 3 Separation of Organic Mixtures and ID
CHM235L - Exp. 3 Separation of Organic Mixtures and ID common problem encountered in chemistry involves the separation of a mixture of two or three compounds into single compound fractions followed by the purification and identification of each.
The two phases are then separated into two fractions: The aqueous sodium hydroxide solution containing the carboxylate anion as its salt and the organic layer containing the neutral organic compound.
If your previous separation of the unknown acid was incomplete, the acid might very well contribute to the spectrum and confuse the issue.
jan.ucc.nau.edu /~jkn/235L3-Separations.htm   (3689 words)

  
 Mixtures - SEPARATION   (Site not responding. Last check: )
A mixture is a combination of 2 or more items (elements or compounds) with different properties which are not chemically combined and which can be separated using one or more of the different properties
Students will record their initial ideas that are related to a mixture and about the possible separation.
One way might be for you to examine the mixture with your magnifier; use the toothpick to move the salt and pepper into two separate piles.
www.mtsu.edu /~pdlee/new_sci442/less_matl/chemistry/chem_mixture.html   (1109 words)

  
 PROCESS FOR MEMBRANE SEPARATION OF GAS MIXTURES (WO9007372A1)
The feed gas side is contacted with a feed gas mixture containing at least one gas to be retained and at least one gas to be separated therefrom.
The partial pressure of certain gas components present on both sides of the membrane are balanced to cause the remaining gas components to diffuse in either direction across the membrane depending upon their differential partial pressures.
    This invention relates to the field of separation of gas mixtures and particularly to the separation of a single component from a mixture of gases.
www.delphion.com /details?pn=WO09007372A1   (303 words)

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