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Chem 6AL Q2 material Questions and
Correct Answers/ Latest Update / Already
Graded
TLC
Ans: thin layer chromatography
liquid
Thin layer chromatography
Ans: a separation technique that involves the separation of
small molecules as they move through a silica gel (polar)
based off polarity
mobile phase
Ans: A liquid that is run through the stationary phase in
chromatography (solvent)
solid phase
Ans: silica plate (polar)
stationary
polar and nonpolar molecules are bound
All rights reserved © 2025/ 2026 |
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What molecules are more attracted to the solid phase
Ans: polar molecules
as the mobile phase travels, what happens to the molecules
Ans: polar molecules spend more time interacting with the
solid phase while nonpolar spend more time in the solvent
resulting in nonpolar molecules having a faster migration rate
Rf value
Ans: distance travelled by solute / distance travelled by solvent
greate Rf = greater migration rate
reverse phase chromatography
Ans: The opposite of traditional thin-layer chromatography, in
which the stationary phase is nonpolar (capped silica)
nonpolar migration rate decreases
polar migration rate increases
All rights reserved © 2025/ 2026 |
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Why is filter paper included into the beaker when preparing the
chamber for TLC
Ans: The purpose of the moistened folded piece of filter paper
inside the chamber is so it can saturate the atmosphere with
solvent vapor, preventing the solvent on the plate from
evaporating during development. This will ensure we have
accurate Rf values and a fast, consistent separation.
Visualizing TLC
Ans: Fluorescent indicator on TLC plate--> visualized using UV
light
compound must be "UV-active" --> conjugation is present
Effect of mobile phase polarity
Ans: Will affect Rf values
Increasing solvent polarity will increase Rf values as the polar
solid phase will choose to interact with the solvent, allowing
both polar and nonpolar molecules to travel further
Decreasing polarity will decrease Rf values
All rights reserved © 2025/ 2026 |
Chem 6AL Q2 material Questions and
Correct Answers/ Latest Update / Already
Graded
TLC
Ans: thin layer chromatography
liquid
Thin layer chromatography
Ans: a separation technique that involves the separation of
small molecules as they move through a silica gel (polar)
based off polarity
mobile phase
Ans: A liquid that is run through the stationary phase in
chromatography (solvent)
solid phase
Ans: silica plate (polar)
stationary
polar and nonpolar molecules are bound
All rights reserved © 2025/ 2026 |
, Page |2
What molecules are more attracted to the solid phase
Ans: polar molecules
as the mobile phase travels, what happens to the molecules
Ans: polar molecules spend more time interacting with the
solid phase while nonpolar spend more time in the solvent
resulting in nonpolar molecules having a faster migration rate
Rf value
Ans: distance travelled by solute / distance travelled by solvent
greate Rf = greater migration rate
reverse phase chromatography
Ans: The opposite of traditional thin-layer chromatography, in
which the stationary phase is nonpolar (capped silica)
nonpolar migration rate decreases
polar migration rate increases
All rights reserved © 2025/ 2026 |
, Page |3
Why is filter paper included into the beaker when preparing the
chamber for TLC
Ans: The purpose of the moistened folded piece of filter paper
inside the chamber is so it can saturate the atmosphere with
solvent vapor, preventing the solvent on the plate from
evaporating during development. This will ensure we have
accurate Rf values and a fast, consistent separation.
Visualizing TLC
Ans: Fluorescent indicator on TLC plate--> visualized using UV
light
compound must be "UV-active" --> conjugation is present
Effect of mobile phase polarity
Ans: Will affect Rf values
Increasing solvent polarity will increase Rf values as the polar
solid phase will choose to interact with the solvent, allowing
both polar and nonpolar molecules to travel further
Decreasing polarity will decrease Rf values
All rights reserved © 2025/ 2026 |
