Separation Flashcards
What is Extraction?
The transfer of a dissolved compound from 1 solvent into another
During extraction, most impurities remain in
The first solvent
How should the two solvents be during extraction?
Immiscible
Extraction separates substances based on
Differential solubility
When an acid dissolves, its formed anion is
More soluble in the aqueous layer
What will extract an acid in the aqueous layer?
Base
Washing is a form of extraction that
Removes unwanted impurities instead of isolating a pure product
Filtration is the act of
Isolating suspended solid from the liquid
Gravity filtration is when the
Solvent is pulled out via gravity
Gravity filtration is done with
Hot solvent
Recrystallization is when
Impure crystals are dissolved in a minimum amount of hot solvent
What happens to the impurities during recrystallization?
The impurities are left in the solution, but crystals form
In recrystallization, the solvent should dissolve pure materials in
Hot temperatures
Impurities should be dissolved in both
Hot and cold temperatures by the solvent
What happens in a mixed solvent system?
Less soluble compound is added to a highly soluble solvent until the solid precipitates
Sublimation is the stage in which a
Heated solid transforms into a gas with no liquid change
Sublimation occurs within vacuums to allow for
Compounds to pass the liquid phase
Sublimation separates solids based on their ability to
Sublimate
Within sublimation, what happens to impurities?
They do not sublime easily
Distillation is the act of
Separating a liquid from another via vaporization and condensation
Distillation requires
Two or more miscible liquids
Simple distillation separates liquids that are
- BP < 150
- 25º away from one another
Vacuum distillation separates liquids that are
- BP > 150
- 25º away from one another
Vacuum distillation operates under
Reduced pressure, which lowers the bp and prevents decomposition
Fractional distillation separates liquids that have
BPs < 25º apart
The vapor near the top in fractional distillation contains eventually
1 component
Chromatography is the separation and identification of individual compounds based on
Differing chemical properties
Chromatography separates components based on their ability to
Adhere to either the stationary or mobile phase
In chromatography, the sample is first loaded into the
Adsorbent (stationary phase)
The mobile phase of chromatography consists of
Fluid being run through to displace the substances
The mobile phase causes for
Separation in the stationary phase
Silica gel is
Polar and hydrophilic
What kind of polarity do the original solvents have in the mobile phase?
Weak to moderate solvents
Which compounds move quickly in weak to moderate polarity?
Nonpolar compounds
What is the adsorbent in TLC?
- A piece of paper
- Thin layer of silica
- Alumina
- Plastic
- Glass Sheet
Individual compounds with TLC can be spotted via
UV light
What is the equation of Rf value?
Distance of compound / Distance of solvent
What happens in Column Chromatography?
Compounds move up and down due to gravity
What are the forms of adsorbents in Column Chromatography?
Silica gel or alumina
In Column Chromatography, the solvent is forced through the column via
N2
Ion-Exchange Column Chromatography, the beads are coated with
Ions
In size-exclusion Column Chromatography, the column has
Beads with tiny pores, allowing large molecules to travel faster
In a GC, what is compared?
Retention time
What happens in HPLC?
Liquid travels though the column under pressure
Electrophoresis separates macromolecules via
Charge
What move faster in Electrophoresis?
Highly charged, small molecules
Agarose is used in Electrophoresis to separate
Nucleic acid pieces
Agarose is stained with
Ethidium Bromide
SDS is used in Electrophoresis to separate
Proteins based on mass
Isoelectric Electrophoresis has a pH at which the
Sum of Amino Acid charges equal to 0
Proteins are protonoated when
pH < pI
Proteins are deprotonoated when
pH is high
In Isoelectric Electrophoresis, proteins move to the pt where
PH = pI
