Analytical Separation Flashcards
(147 cards)
1
Q
These are useful when there is a significant difference in at least one of the chemical or physical properties between analyte and interferences
A
Separation techniques
2
Q
What are the classification of separation techniques
A
(1) Basis of Separation
(2) Separation Technique/s
2
Q
What are the various basis of separation
A
size
mass or density
complex formation
change in physical state
change in chemical state
partitioning between phases
2
Q
separation techniques for size
A
filtration
dialysis
size-exclusion chromatography
2
Q
What are the different separation techniques
A
filtration
dialysis
size-exclusion chromatography
centrifugation
masking
distillation
sublimation
recrystallization
precipitation
electrodeposition
volatilization
extraction
chromatography
3
Q
separation technique for mass or density
A
centrifugation
4
Q
separation technique for complex formation
A
masking
4
Q
separation techniques for change in physical state
A
distillation
sublimation
recrystallization
5
Q
separation techniques for change in chemical state
A
precipitation
electrodeposition
volatilization
5
Q
separation techniques for partitioning between phases
A
extraction
chromatography
5
Q
The substance that remains in the filter paper (ex. mud) is called
A
residue
5
Q
The clear liquid or the substance collected after filtration is called
A
filtrate
6
Q
it is the method of separating insoluble impurities or substances from a liquid
A
filtration
6
Q
other term for seize exclusion chromatography
A
gel filtration chromatography or SEC
7
Q
It is used for protein purification and separates molecules based on size
A
Size Exclusion Chromatography
8
Q
Molecules are separated based on their size and are eluted in order of decreasing molecular weight
A
Size Exclusion Chromatography
9
Q
Molecules are separated based on their size and are eluted in order of ________________________________
A
decreasing molecular weight
10
Q
SEC Workflow (steps)
A
- 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
11
Q
Where is SEC useful?
A
- Desalting
- Fractionation
12
Q
It is the movement of solute molecules from an area of higher concentration to an area of lower concentration
A
diffusion
12
Q
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
A
osmosis
13
Q
It is the process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrane
A
dialysis
14
Q
These three have importance in biological processes
A
Diffusion, Osmosis, and Dialysis
15
Q
It is the process of separation of insoluble materials from a liquid when normal filtration does not work well
A
Centrifugation
15
It is based on size, shape, density of the particles, viscosity of the medium, and the speed of rotation
Centrifugation
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centrifugation is based on:
size
shape
the density of the particles
viscosity of the medium
speed of rotation
17
Its principle is that when spun rapidly, the denser particles are forced to the bottom and the lighter particles stay at the top
Centrifugation
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It is the apparatus used for centrifugation
Centrifuge
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It is the centrifuge tube holder in a centrifuge
Rotor
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It utilizes differences in solubility
extraction
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It utilizes differences in polarity
chromatography
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It utilizes differences in boiling points
distillation
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Extraction utilizes differences in ______________
solubility
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Chromatography utilizes difference in _______________
polarity
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Distillation utilizes differences in _____________________
boiling points
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Mixture of two ____________________ with very disparate boiling points
miscible liquids
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The ________________ will cause the temperature inside the condenser to drop
cold water
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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
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After distillation, the condensed vapor is often called the
distillate
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It refers to the liquid product that is collected after the vapor has been condensed and separated through the distillation process
distillate
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It is useful for performing separations
distillation
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It utilizes a fractionating column to separate mixtures with many components, like the atmosphere, or certain mixtures with industrial applications
Fractional distillation
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It is useful for running reactions
distillation
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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
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These are examples of such an azeotrope, where special techniques are needed for such mixtures
ethanol and water
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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
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mixture of ammonium chloride and chalk powder can be separated by the method of
sublimation
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It is the property of substance in which it is converted directly from solid to gas or vice versa
sublimation
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substances converted directly from solid to gas or vice versa
sublime
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Some example of solids which sublimes are
- ammonium chloride
- camphor
- naphthalene
- anthracene
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one technique for the purification of solids
Recrystallization
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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
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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)
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It is a powerful process for the purification of solids
Recrystallization
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Solvent selection may require trial and error needs
- polarity of the solvent
- tabulated solubility data
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This will increase as a result of the recrystallization process
Purity
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It can kick start crystallization
seed crystal
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collect the crystals by _____________
filtration
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it happens when chemical in a solution react to form a solid
Precipitation Reactions
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Dissolved substances producing solids
Precipitation Reactions
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Ions dissociating and rebonding
Precipitation Reactions
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One of the best ways to produce chemical of the highest purity
Precipitation Reactions
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These are what create geological deposits in the earth
Precipitation Reactions
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This is good at dissolving, particularly ionic compounds
water
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Water is good at dissolving, particularly ________ compounds
ionic
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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
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_______________ in the water reacted with ionic compounds, or salts, in the limestone to make insoluble silver compounds that fell out of solution
silver ions
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Getting the silver out of silver chloride will involve another kind of reaction, a _______________________
redox reaction
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It is a crystalline solid that is not very soluble in water
silver chloride
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Spectator ions: _________ and _________, does not participate directly in the reaction
nitrate, sodium
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It is a process in which metal atoms are transported onto the surface of another metal using electricity
electroplating
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what are the various uses of electroplated materials
chromium plating
gold plating
zinc plating
tin plating
titanium plating
silver plating
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It is commonly used for decorative purposes and for preventing corrosion
Electroplating
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As a result of ____________________, the metal surface is plated in a thin layer of the imported atoms
electroplating process
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The most common metals used in electroplating are:
copper
nickel
chromium
tin
gold
silver
platinum
palladium
zinc
rhodium
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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
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Chromium provides?
corrosion resistance
increase surface hardness
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It is also used for providing corrosion resistance
zinc
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The process of zinc electroplating is generally called?
galvanization
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Zinc is plated onto _____or ______, to prevent rusting
steel, iron
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The zinc layer sacrifices itself and rusts over time, so the plated material is protected and this process is called?
sacrifice plating
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Zinc is plated onto steel or iron, to prevent?
rusting
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Electroplating is carried out with a special device called an?
electrolytic cell
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An electrolytic cell consists of?
DC battery
electrodes
electrolytic solution
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The electrode, where atoms give electrons is called the?
anode
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oxidation reactions are carried out in the?
anode
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Reduction reactions are carried out in the?
cathode
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The electrode, where atoms gain electrons is called the?
cathode
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In electroplating, the anode should be ______________ charged
positively
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In electroplating, the cathode should be _______________ charged
negatively
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The metal to be used for plating must be connected to the?
anode
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the metal to be plated must be connected to the?
cathode
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the ____________________ must be a solution of a salt of the metal used for the anode
electrolytic solution
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the electrolytic solution must be a solution of a salt of the metal used for the _________
anode
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the electrolytic solution must be a solution of a _______ of the metal used for the anode
salt
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When the current is turned on, positively charged cations move to the _______, and negatively charged anions move to the anode
cathode
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these moves to the anode when the current is turned on
negatively charged anions
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When the current is turned on, positively charged cations move to the cathode, and negatively charged anions move to the ________
anode
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these moves to the cathode when the current is turned on
positively charged cations
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Cathode gain electrons and become?
neutral
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These typically become solid when in their neutral form
metal atoms
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metals atom are typically solid when in their?
neutral form
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those which _________________ become solid and build upon the cathode
gain electrons
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On the anode, a compound ______ electrons because of the current
lose
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On the anode, a compound lose electrons because of the current, therefore, these atoms move to the _________ and become solid
cathode
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The _______ mass decreases and the __________ is plated
anode’s, cathode
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It is used to calculate the quantity of analyte in a sample
Volatilization gravimetry
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what is the other term for electroplating process
electrodeposition
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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
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This means the conversion of a substance to the gas phase
Volatilization
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It is an analytical method used to measure mass or change in mass to quantify an analyte
Gravimetry or gravimetric analysis
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It is a mass analysis method that uses thermal or chemical energy to separate substances in order to measure their masses
Volatilization gravimetry
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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
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The loss of water vapor from a hydrated salt is a specific example of?
volatilization gravimetry
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Water molecules that form part of a salt crystal lattice structure are specifically referred to as?
water of crystallization or water of hydration
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We can determine the mass of water of crystallization in a salt using?
volatilization gravimetry
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It is a salt containing water molecules within its structure
Hydrated salt
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This refers to a salt that does not contain water of crystallization
Anhydrous
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The mass of dehydrated salt can be determined by?
weighing
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The mass of the anhydrous salt is ______________ than the hydrated salt because of the loss of water
smaller
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The mass of the anhydrous salt is smaller than the hydrated salt because of the?
loss of water
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The mass of this water lost can be determined by the difference in the masses between the?
hydrated and dehydrated salts
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This __________________________ of dehydrated salt is what we will use in calculations
unchanging constant mass
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The reverse reaction is promoted by the?
addition of water and cooling
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It is also useful to determine the coefficient for the water of crystallization it is unknown
Volatilization gravimetry
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We can also use the various masses determine from a volatilization experiment to calculate the ______________________________ in a hydrated salt
percentage of water of crystallization
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We will rely on _____________ and ________________in separating mixtures with smaller particles
solubility, reactivity
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Use of ____________________ to separate with ease
physical properties
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It is an ionic compound that is water soluble
Sodium chloride
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It is a steroid which is a type of lipid, and is therefore water insoluble
cholesterol
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Non-polar solvent like ________ will easily dissolve nonpolar and water insoluble compounds
ether
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It means do not mix
immiscible
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Two layers will be formed, on the bottom is the _____________ since it is denser, and on the top is the ________________
aqueous layer, organic layer
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It is trickier to separate
having similar solubilities
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It is much easier to separate
having different solubilities
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It is a drying agent
sodium sulfate
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It is ubiquitous in the organic chemistry laboratory
Extraction
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Most reactions end by quenching via some _________________ followed by extraction in a separatory funnel
aqueous workup
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Most reactions end by quenching via some aqueous workup followed by _______________ in a separatory funnel
extraction
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These will be diluted along the paper
Individual components
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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
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Dyes which are more soluble in the solvent will migrate ___________ and _____________ along the chromatography paper
faster, further
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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
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Marking the solvent front is crucial for calculation of the?
Rf values
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This type of dye will not migrate
insoluble
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Sample spots should be?
above solvent level
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What happens if the sample spots are below the solvent level?
the inks cannot be separated
