pre lab quiz 5 Flashcards
It means color writing
Chromatography
Chromatography literally means
Color writing
Chromatography is a method of separating the…
Components of the mixture
Chromatography is widely used for _____ and _____ analyses or for _____ and _____ of the components of a mixture
Quantitative
Qualitative
Isolation
Recovery
These components have different affinities and distributes between 2 phase:
Stationary phase
Mobile phase
The mobile which can be a ____ or a _____, that moves in ___________ and passes over the ______
Liquid
Gas
Definite direction
Stationary phase
The components of the mixture are introduced at _____
One end of the stationary phase
As the stationary and mobile phase interacts with one another, different compounds migrate at ____ and ______ based on their ____.
Different rates
Separate from one another
Affinities
A substance that has stronger attractive forces with the ______ will migrate more _______ than a substance that has weaker attractive force
Stationary phase
Slowly
The ability of a substance to ______ in and move with the _____ phases enables it to travel more easily over the _____ phase
Dissolve
Mobile
Stationary
What are the 4 types of chromatography
TLC
LC
HPLC
GC
The most suitable chromatography is based on
1)
2)
3)
to separate
1) purpose of the separation
2) available resources
3) properties of the compounds
In this experiment, thin layer chromatography will be used to analyze the _____ from the previous experiment
Extracted caffeine
TLC is ____, ____ , ____, _____ and it requires only _____ quantities of material
Simple, inexpensive, fast and efficient
Small
In TLC, various materials can be used as the _____ phase
Stationary phase
_____, _____, or _____ are coated with a thin layer of adsorbent, can be used as a stationary phase
Glass
Metals
Plastic plates
Glass, metals or plastic plates are coated with a_____, can be used as a stationary phase
Thin layer of absorbent
The mobile phase is _____ solvent or a _____ of solvents
Pure
Mixture
The appropriate composition of the mobile phase depends on the _____ in the mixture being separated
Polarities of the compound
The stationary phase is usually ____ - _____ is _____ widely used
Polar - silica gel
Most
The stationary phase is polar -
Silica gel is most widely used
What is the formula of the Rf
Distance traveled by the solute (mm) / distance traveled by the solvent form (mm)
What are 3 objectives of this activity
Perform thin layer chromatography
Check the purity of the extracted crude caffeine from previous experiment
Calcite the Rf value of the crude caffeine
What are the reagents used (MIC)
Methanol
Iodine crystals
Chloroform
What are the needed glassware
2 beaker 250ml
2 beaker 100ml
2 test tube
2 watch glass
1 stirring rod
1 graduated cylinder
1 capillary tubes
What is the instrument used
UV lamp
To perform TLC analysis, a small amount of the mixture is being separated is dissolved in a _____ and applied or spotted onto the ____________
Suitable solvent
Adsorbent near one end of a TLC plate
Then, the plate is places in a closed chamber with the edge nearest the ______ immersed in a _____ layer of the _____ phase called the, ______
applied spot
shallow
mobile phase
developing solvent
Where is the plate placed at
Closed developing chamber
The solvent rises through the stationary phase by _______ , a process called developing the chromatogram
capillary action
The solvent rises the rough the stationary phase by capillary action, a process called ______
Developing the chromatogram
After allowing the chromatogram to develop,
the _____ can be marked and
the distance travelled by the ________ and ______ can be measured
Spots
Solvent front
Spots
Rf
Retardation factor
It is a dimensionless quantity that can be used as a measure of the affinity of the spot towards the stationary or mobile phase
Rf - retardation factor
High value of Rf =
High affinity towards the mobile phase
Do not look directly in the…
Uv lamp
What can be disposed directly to the sink with running water
Diluted aq solutions
Acid wastes that can be diluted with water
Chloroform molecular formula
CHCl3
