Analytical Separation Flashcards
These are useful when there is a significant difference in at least one of the chemical or physical properties between analyte and interferences
Separation techniques
What are the classification of separation techniques
(1) Basis of Separation
(2) Separation Technique/s
What are the various basis of separation
size
mass or density
complex formation
change in physical state
change in chemical state
partitioning between phases
separation techniques for size
filtration
dialysis
size-exclusion chromatography
What are the different separation techniques
filtration
dialysis
size-exclusion chromatography
centrifugation
masking
distillation
sublimation
recrystallization
precipitation
electrodeposition
volatilization
extraction
chromatography
separation technique for mass or density
centrifugation
separation technique for complex formation
masking
separation techniques for change in physical state
distillation
sublimation
recrystallization
separation techniques for change in chemical state
precipitation
electrodeposition
volatilization
separation techniques for partitioning between phases
extraction
chromatography
The substance that remains in the filter paper (ex. mud) is called
residue
The clear liquid or the substance collected after filtration is called
filtrate
it is the method of separating insoluble impurities or substances from a liquid
filtration
other term for seize exclusion chromatography
gel filtration chromatography or SEC
It is used for protein purification and separates molecules based on size
Size Exclusion Chromatography
Molecules are separated based on their size and are eluted in order of decreasing molecular weight
Size Exclusion Chromatography
Molecules are separated based on their size and are eluted in order of ________________________________
decreasing molecular weight
SEC Workflow (steps)
- Insert sample in column
- Proteins collect at the top of the column
- Proteins separate based on size
- Proteins exit from the largest to the smallest
Where is SEC useful?
- Desalting
- Fractionation
It is the movement of solute molecules from an area of higher concentration to an area of lower concentration
diffusion
It is the diffusion of solvent across a semipermeable membrane, the movement solvent molecules from a region of lower solute concentration to a region of higher solute concentration
osmosis
It is the process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrane
dialysis
These three have importance in biological processes
Diffusion, Osmosis, and Dialysis
It is the process of separation of insoluble materials from a liquid when normal filtration does not work well
Centrifugation
It is based on size, shape, density of the particles, viscosity of the medium, and the speed of rotation
Centrifugation
centrifugation is based on:
size
shape
the density of the particles
viscosity of the medium
speed of rotation
Its principle is that when spun rapidly, the denser particles are forced to the bottom and the lighter particles stay at the top
Centrifugation
It is the apparatus used for centrifugation
Centrifuge
It is the centrifuge tube holder in a centrifuge
Rotor
It utilizes differences in solubility
extraction
It utilizes differences in polarity
chromatography
It utilizes differences in boiling points
distillation
Extraction utilizes differences in ______________
solubility
Chromatography utilizes difference in _______________
polarity
Distillation utilizes differences in _____________________
boiling points
Mixture of two ____________________ with very disparate boiling points
miscible liquids
The ________________ will cause the temperature inside the condenser to drop
cold water
The cold water will cause the temperature inside the condenser to drop, so when the vapor enters this section, it will ______________ back into a liquid
condense
After distillation, the condensed vapor is often called the
distillate
It refers to the liquid product that is collected after the vapor has been condensed and separated through the distillation process
distillate
It is useful for performing separations
distillation
It utilizes a fractionating column to separate mixtures with many components, like the atmosphere, or certain mixtures with industrial applications
Fractional distillation
It is useful for running reactions
distillation
It is a mixture of two or more liquids that when boiled, the vapor will contain those constituents in the same proportion as the liquid, and it will boil at a temperature lower than any of their individual boiling points
Azeotope
These are examples of such an azeotrope, where special techniques are needed for such mixtures
ethanol and water
Distillation Tips
- Make sure your distillation flask is not more than half full
- Make sure your thermometer is in the correct position
- Make sure your heat source is easy to remove very quickly
- Make sure everything is clamped and clipped
- You may collect distillate only at the desired temperature range
mixture of ammonium chloride and chalk powder can be separated by the method of
sublimation
It is the property of substance in which it is converted directly from solid to gas or vice versa
sublimation
substances converted directly from solid to gas or vice versa
sublime
Some example of solids which sublimes are
- ammonium chloride
- camphor
- naphthalene
- anthracene
one technique for the purification of solids
Recrystallization
It is used to solve when the lattice structure is forming during the precipitation, ions, and other particles that do not belong in the lattice will get trapped inside and disrupt the pattern of the lattice
Recrystallization
Recrystallization needs a solvent that offers:
- low solubility at room temp. (will recrystallize upon cooling)
- high solubility at high temp. (will dissolve upon heating)
- high solubility for the impurity at room temperature (stays dissolved)
- or low solubility for the impurity at high temp. (never dissolves)
It is a powerful process for the purification of solids
Recrystallization
Solvent selection may require trial and error needs
- polarity of the solvent
- tabulated solubility data
This will increase as a result of the recrystallization process
Purity
It can kick start crystallization
seed crystal
collect the crystals by _____________
filtration
it happens when chemical in a solution react to form a solid
Precipitation Reactions
Dissolved substances producing solids
Precipitation Reactions
Ions dissociating and rebonding
Precipitation Reactions
One of the best ways to produce chemical of the highest purity
Precipitation Reactions
These are what create geological deposits in the earth
Precipitation Reactions
This is good at dissolving, particularly ionic compounds
water
Water is good at dissolving, particularly ________ compounds
ionic
Some ionic compounds can overcome even the dissolving power of water, and when they form through reactions in solution, they fall out as a ___________________
solid precipitate
_______________ in the water reacted with ionic compounds, or salts, in the limestone to make insoluble silver compounds that fell out of solution
silver ions
Getting the silver out of silver chloride will involve another kind of reaction, a _______________________
redox reaction
It is a crystalline solid that is not very soluble in water
silver chloride
Spectator ions: _________ and _________, does not participate directly in the reaction
nitrate, sodium
It is a process in which metal atoms are transported onto the surface of another metal using electricity
electroplating
what are the various uses of electroplated materials
chromium plating
gold plating
zinc plating
tin plating
titanium plating
silver plating
It is commonly used for decorative purposes and for preventing corrosion
Electroplating
As a result of ____________________, the metal surface is plated in a thin layer of the imported atoms
electroplating process
The most common metals used in electroplating are:
copper
nickel
chromium
tin
gold
silver
platinum
palladium
zinc
rhodium
It is a metal which has high corrosion resistance and its appearance is aesthetically pleasing, so chrome plating is used for decorative purposes, providing corrosion resistance and increasing surface hardness
chromium
Chromium provides?
corrosion resistance
increase surface hardness
It is also used for providing corrosion resistance
zinc
The process of zinc electroplating is generally called?
galvanization
Zinc is plated onto _____or ______, to prevent rusting
steel, iron
The zinc layer sacrifices itself and rusts over time, so the plated material is protected and this process is called?
sacrifice plating
Zinc is plated onto steel or iron, to prevent?
rusting
Electroplating is carried out with a special device called an?
electrolytic cell
An electrolytic cell consists of?
DC battery
electrodes
electrolytic solution
The electrode, where atoms give electrons is called the?
anode
oxidation reactions are carried out in the?
anode
Reduction reactions are carried out in the?
cathode
The electrode, where atoms gain electrons is called the?
cathode
In electroplating, the anode should be ______________ charged
positively
In electroplating, the cathode should be _______________ charged
negatively
The metal to be used for plating must be connected to the?
anode
the metal to be plated must be connected to the?
cathode
the ____________________ must be a solution of a salt of the metal used for the anode
electrolytic solution
the electrolytic solution must be a solution of a salt of the metal used for the _________
anode
the electrolytic solution must be a solution of a _______ of the metal used for the anode
salt
When the current is turned on, positively charged cations move to the _______, and negatively charged anions move to the anode
cathode
these moves to the anode when the current is turned on
negatively charged anions
When the current is turned on, positively charged cations move to the cathode, and negatively charged anions move to the ________
anode
these moves to the cathode when the current is turned on
positively charged cations
Cathode gain electrons and become?
neutral
These typically become solid when in their neutral form
metal atoms
metals atom are typically solid when in their?
neutral form
those which _________________ become solid and build upon the cathode
gain electrons
On the anode, a compound ______ electrons because of the current
lose
On the anode, a compound lose electrons because of the current, therefore, these atoms move to the _________ and become solid
cathode
The _______ mass decreases and the __________ is plated
anode’s, cathode
It is used to calculate the quantity of analyte in a sample
Volatilization gravimetry
what is the other term for electroplating process
electrodeposition
In _________________, a sample, whether it be a compound or a mixture, is heated or allowed to undergo a chemical reaction, and the volatile components are liberated and are thus separated from the remaining components of the sample
volatilization
This means the conversion of a substance to the gas phase
Volatilization
It is an analytical method used to measure mass or change in mass to quantify an analyte
Gravimetry or gravimetric analysis
It is a mass analysis method that uses thermal or chemical energy to separate substances in order to measure their masses
Volatilization gravimetry
Examples of volatile compounds which may be released during chemical or thermal decomposition of a sample include:
nitrogen gas
chlorine gas
carbon dioxide gas
water vapor
The loss of water vapor from a hydrated salt is a specific example of?
volatilization gravimetry
Water molecules that form part of a salt crystal lattice structure are specifically referred to as?
water of crystallization or water of hydration
We can determine the mass of water of crystallization in a salt using?
volatilization gravimetry
It is a salt containing water molecules within its structure
Hydrated salt
This refers to a salt that does not contain water of crystallization
Anhydrous
The mass of dehydrated salt can be determined by?
weighing
The mass of the anhydrous salt is ______________ than the hydrated salt because of the loss of water
smaller
The mass of the anhydrous salt is smaller than the hydrated salt because of the?
loss of water
The mass of this water lost can be determined by the difference in the masses between the?
hydrated and dehydrated salts
This __________________________ of dehydrated salt is what we will use in calculations
unchanging constant mass
The reverse reaction is promoted by the?
addition of water and cooling
It is also useful to determine the coefficient for the water of crystallization it is unknown
Volatilization gravimetry
We can also use the various masses determine from a volatilization experiment to calculate the ______________________________ in a hydrated salt
percentage of water of crystallization
We will rely on _____________ and ________________in separating mixtures with smaller particles
solubility, reactivity
Use of ____________________ to separate with ease
physical properties
It is an ionic compound that is water soluble
Sodium chloride
It is a steroid which is a type of lipid, and is therefore water insoluble
cholesterol
Non-polar solvent like ________ will easily dissolve nonpolar and water insoluble compounds
ether
It means do not mix
immiscible
Two layers will be formed, on the bottom is the _____________ since it is denser, and on the top is the ________________
aqueous layer, organic layer
It is trickier to separate
having similar solubilities
It is much easier to separate
having different solubilities
It is a drying agent
sodium sulfate
It is ubiquitous in the organic chemistry laboratory
Extraction
Most reactions end by quenching via some _________________ followed by extraction in a separatory funnel
aqueous workup
Most reactions end by quenching via some aqueous workup followed by _______________ in a separatory funnel
extraction
These will be diluted along the paper
Individual components
The advantages of using chromatography are:
only a small sample is required
it can be used as a method to determine if the sample is pure
Dyes which are more soluble in the solvent will migrate ___________ and _____________ along the chromatography paper
faster, further
It is the technique used to separate small amount of substances from a mixture based on the different solubilities of the components in the particular solvent
Chromatography
Marking the solvent front is crucial for calculation of the?
Rf values
This type of dye will not migrate
insoluble
Sample spots should be?
above solvent level
What happens if the sample spots are below the solvent level?
the inks cannot be separated
