CHEM 232 Experiment 7 Exam Questions and Answers Fully Solved Latest Version 2025-2026
What is gas chromatography - Answers An analytical technique of separation and analysis with
a mobile and stationary phase.
What is the basis of GC - Answers Volatility or boiling point
What is GC limited to - Answers compounds that can exist in the gas phase
What can not be separated by GC? - Answers Large biological molecules
Is GC more of an analytical tool or a preparatory one and why? - Answers Analytical, because it
is destructive and the sample can not be retrieved at the end
In a GC, where is the stationary phase? - Answers Coated on the walls
In GC, where is the mobile phase and what is it - Answers It is flowering and is an inert gas such
as helium in our lab. It pushes the sample along the column
Is the sample in the gas phase or liquid phase, or both? - Answers It spends part of the time in
the gas phase being pushed along the column by the mobile phase and part of the time
interacting with the stationary phase being retained in the column
A compound with a lower boiling point needs ___ energy in order to get to the gas phase? -
Answers Less
What is the stationary phase in our lab composed of? - Answers 95% silicone oil and 5% phenyl
methyl silicone oil which has a very high boiling point and is relatively non polar
How can we change the time and reslution in GC - Answers By changing the flow rate of the
mobile phase gas and the temperature in the column
Increasing the temperature... - Answers gives compunds more energy and they spend more time
in the gas phase, shortening the analysis time but DECREASING the reoslution
Increasing the flow rate... - Answers will push hte samples faster through the colun giving the
mixture less time to separate
Can we change the column length in our lab? - Answers No
When is the best separation usually achieved - Answers When the temperature is held constant
and it is in between the boiling point of a two-component mixture
What happens once the sample exits the column? - Answers It goes to a flame ionization
detector (FID)
When must we use a response factor - Answers when comparing the quantities of samples that
do not have the same molecular formula
What is gas chromatography - Answers An analytical technique of separation and analysis with
a mobile and stationary phase.
What is the basis of GC - Answers Volatility or boiling point
What is GC limited to - Answers compounds that can exist in the gas phase
What can not be separated by GC? - Answers Large biological molecules
Is GC more of an analytical tool or a preparatory one and why? - Answers Analytical, because it
is destructive and the sample can not be retrieved at the end
In a GC, where is the stationary phase? - Answers Coated on the walls
In GC, where is the mobile phase and what is it - Answers It is flowering and is an inert gas such
as helium in our lab. It pushes the sample along the column
Is the sample in the gas phase or liquid phase, or both? - Answers It spends part of the time in
the gas phase being pushed along the column by the mobile phase and part of the time
interacting with the stationary phase being retained in the column
A compound with a lower boiling point needs ___ energy in order to get to the gas phase? -
Answers Less
What is the stationary phase in our lab composed of? - Answers 95% silicone oil and 5% phenyl
methyl silicone oil which has a very high boiling point and is relatively non polar
How can we change the time and reslution in GC - Answers By changing the flow rate of the
mobile phase gas and the temperature in the column
Increasing the temperature... - Answers gives compunds more energy and they spend more time
in the gas phase, shortening the analysis time but DECREASING the reoslution
Increasing the flow rate... - Answers will push hte samples faster through the colun giving the
mixture less time to separate
Can we change the column length in our lab? - Answers No
When is the best separation usually achieved - Answers When the temperature is held constant
and it is in between the boiling point of a two-component mixture
What happens once the sample exits the column? - Answers It goes to a flame ionization
detector (FID)
When must we use a response factor - Answers when comparing the quantities of samples that
do not have the same molecular formula
