define  vacuum distillation?
358811
What he said, plus vacuum distillation reduces the boiling points of substances. This is frequently used to prevent denaturization of more fragile compounds.
216232
its either desalnation or distillation
429325
A rotary evaporator is a device used in chemical and biochemical laboratories for the efficient and gentle evaporation of solvents. The main components of a rotary evaporator are a vacuum system, consisting of a vacuum pump and a controller, a rotating evaporation flask which can be heated in a heated fluid bath, and a condenser with a condensate collecting flask. The system works because lowering the pressure lowers the boiling point of liquids and thus the solvent. This allows the solvent to be removed without excessive heating.\n\nEvaporation under vacuum can be performed in a standard distillation rig. However, the Rotavapor has a key advantage. As the evaporating flask rotates, the liquids are forced to the outside of the flask with the centrifugal force. This creates a larger surface area of the liquids and hence allows for quicker evaporation.\n\nRotary evaporators are highly effective at removing the majority of organic solvents during the extraction process but are not recommended for extractions that use water as a solvent due to its high boiling temperature.\n\nThe rotary evaporator was invented by Swiss company Büchi. The Büchi Rotavapor continues to be the most widely used rotary evaporator, and Rotavapor has become a synonym for such instruments. Other manufacturers include IKA and Heidolph.\n\nThe most common form is the benchtop rotary evaporator, though large scale (20 L) versions are available and are used by pilot plants in large pharmaceutical companies.
1166443
It is not possible to obtain absolute alcohol by simple fractional distillation, because a mixture containing around 95.5% alcohol and 4.5% water becomes an azeotropic mixture. In one common industrial method to obtain 100% pure alcohol, a small quantity of benzene is added to rectified spirit and the mixture is then distilled. Because a small amount of the benzene used remains , the solution is carcinogenic. So production of absolute alcohol is done by desiccation using glycerol. Alcohol produced by this method is known as spectroscopic alcohol.
503418
vaporization, change of a liquid or solid substance to a gas or vapor. There is fundamentally no difference between the terms gas and vapor, but gas is used commonly to describe a substance that appears in the gaseous state under standard conditions of pressure and temperature, and vapor to describe the gaseous state of a substance that appears ordinarily as a liquid or solid. Although most substances undergo changes of state in the order of solid to liquid to gas as the temperature is raised, a few change directly from solid to gas in a process known as sublimation.\n\nLiquids can also change to gases at temperatures below their boiling points. Vaporization of a liquid below its boiling point is called evaporation, which occurs at any temperature when the surface of a liquid is exposed in an unconfined space. When, however, the surface is exposed in a confined space and the liquid is in excess of that needed to saturate the space with vapor, an equilibrium is quickly reached between the number of molecules of the substance going off from the surface and those returning to it. A change in temperature upsets this equilibrium; a rise in temperature, for example, increases the activity of the molecules at the surface and consequently increases the rate at which they fly off. When the temperature is maintained at the new point for a short time, a new equilibrium is soon established.\n\nThe pressure exerted by the vapor of a liquid in a confined space is called its vapor pressure. It differs for different substances at any given temperature, but each substance has a specific vapor pressure for each given temperature. At its boiling point the vapor pressure of a liquid is equal to atmospheric pressure. For example, the vapor pressure of water, measured in terms of the height of mercury in a barometer, is 4.58 mm at 0°C and 760 mm at 100°C (its boiling point).
259804
You have a beaker with an outlet for a rubber hose that is connected to the side running water outlet. On top of the beaker you have a funnel with a piece of filter paper in it. The running water creates a slight vacuum in the beaker. According to the Ideal Gas Law, the pressure in the beaker is lower than that outside of the beaker, causing it to suck in some air in order to equalize the pressure.Now, when you put in a liquid containing solids, the liquid will get sucked through the filter paper, leaving you with the solid. Vacuum Filtration is sometimes used instead of normal filtration because of its better filtration.( Normal filtration uses gravity instead of a vacuum)
33182
We'd need a formula editor to do this...\n\nPressure difference delta-p must equal vapour pressure p(x) in order to get the vacuum on top of a manometer.\n\nPressure is force F divided by area a.\n\nF is mass m times gravity acceleration g\n\nmass m is density rho times volume V\n\nThe column inside the manometer exerts a pressure \n\np(i) = g * rho * V / a\n\ng: gravity acceleration\nrho: density\nV: volume V=h*a\na: area\nh: height  h=V/a\n\nso we get\n\np(i) = g * rho * h
794147
You might work up some Q&A while showing this old demo of the effect of atm pressure...thereby adding some visual interest to the subject.\n\nAdd a few oz of water to a square-sided, metal, one-gallon can having a tightly fitted cap...bring to a vigorous boil (cap now off, please :-))..) and continue boiling until all air is expelled...screw cap in place and allow to cool...they will see the can collapse.\n\nWork up questions about the vacuum thus created (by the condensation of the water vapor) allowing atm pressure to exert its force.
1135756
Sublimation is a method that converts a solid directly to gas without changing into the liquid state. Examples are : - camphor, naphthalene, anthracene etc
738985
physical methods of separation; distillation, filtration, centrifugation, etc.\nChemical methods: sublimation, crystallization,  chromatography (actually, a combination of the chemical properties of the solubilty of the item in solution, and physical separation of stubstances via filter paper)
227415
actual pressure of the vapour\ndivided by\nthe maximum pressure of the vapour at 'that' temperature\nequals (in this case) 1 = 100%
1142120
one is distillation & thee other is desalination
220194
Filtration\nEvaporation\nCentrifugation\nPercipitation\nDistillation\nFractional Distillation\nMagnetism\nSeperating Funnel
1156050
I would visit the site cited below.  The discussion includes:\n\n"Irving Langmuir developed a way to measure vapor pressure \nby measuring the evaporation rate, which we will now flip around backwards. His reasoning is that the rate at which molecues are lost due to evaporation to a gas with no partial pressure of the evaporating substance is the same as the rate at which molecules of the substance would hit the surface if it were in equilibrium with the vapor (because in equilibrium the evaporation rate and re-condensation rate cancel each other out). His expression is: \n\n(mass loss rate)/(unit area) = (vapor pressure - ambient partial pressure)*sqrt( (molecular weight)/(2*pi*R*T) ) "
784896
fractional distillation
300959
This is typically called a cloud chamber.  I built one many years ago as a science project.\n\nWhat you do is create a sealed chamber that in which the air is oversaturated with a fluid, typically water or alcohol.  Heavy charged particles pass through the chamber and disturb the super-saturated atmosphere, causing a vapor trail.  You can see the trail of the particles, you can't really identify or see the actual particle.
1168680
To purify (separate) the product you want from impurities. For example, if you wanted to separate a mix of alcohol and water, you would use the distillation flask along with a heating mantle (like a Bunsen burner, but designed for flasks) to heat the mixture; because alcohol has a lower boiling point than water, it would evaporate faster and re-condense in the collection flask, leaving water in the distillation flask.