CHEM LAB EXAM STUDY GUIDE
CHEM LAB EXAM STUDY
GUIDE. GRADED A+.
QUESTIONS AND 100%
VERIFIED ANSWERS. LATEST
2025/2026 UPDATE
Calculate the Rf value for a spot in a TLC experiment if the solvent moved 12.5
cm and the spot moved 7.2 cm from the origin. - ANS✔✔-0.576
In a TLC experiment, the Rf value represents the fraction that the mixture
component travelled compared to the whole distance travelled by the mobile
phase. The equation to calculate Rf is
Rf=distance travelled by mixture component / distance travelled by mobile
phase
In the question, the solvent is the mobile phase and the spot is the mixture
component. Thus, you can plug the given values into the equation.
, CHEM LAB EXAM STUDY GUIDE
Rf=7.2 cm/12.5 cm
After performing a TLC experiment, you might place the TLC plate in a
container with iodine crystals.
What is the purpose of the iodine crystals? - ANS✔✔-The crystals create a gas
that reacts with organic compounds to help see them on the plate.
The iodine crystals in the container sublime into iodine gas. The iodine gas
reacts with many organic compounds, making them appear brown. The colored
appearance helps visualize the spots on the TLC plate.
Identify the chromatography term that corresponds to each definition.
The substance that carries the components of a mixture
Choose...mobile phase
A value that quantifies the distance traveled by a substance relative to the
distance traveled by the solvent
Choose...Rf
The substance to which the sample is bound at the start of an experiment
Choose...stationary phase
A method used to separate components of a mixture
Choose...chromatography - ANS✔✔-Be sure to review all terms associated with
chromatography prior to starting the procedure. In order for a chromatography
experiment to work, it is necessary to pay careful attention to each variable in
the experiment.
Aspirin is usually packaged with
Choose...buffering agent to reduce its
CHEM LAB EXAM STUDY
GUIDE. GRADED A+.
QUESTIONS AND 100%
VERIFIED ANSWERS. LATEST
2025/2026 UPDATE
Calculate the Rf value for a spot in a TLC experiment if the solvent moved 12.5
cm and the spot moved 7.2 cm from the origin. - ANS✔✔-0.576
In a TLC experiment, the Rf value represents the fraction that the mixture
component travelled compared to the whole distance travelled by the mobile
phase. The equation to calculate Rf is
Rf=distance travelled by mixture component / distance travelled by mobile
phase
In the question, the solvent is the mobile phase and the spot is the mixture
component. Thus, you can plug the given values into the equation.
, CHEM LAB EXAM STUDY GUIDE
Rf=7.2 cm/12.5 cm
After performing a TLC experiment, you might place the TLC plate in a
container with iodine crystals.
What is the purpose of the iodine crystals? - ANS✔✔-The crystals create a gas
that reacts with organic compounds to help see them on the plate.
The iodine crystals in the container sublime into iodine gas. The iodine gas
reacts with many organic compounds, making them appear brown. The colored
appearance helps visualize the spots on the TLC plate.
Identify the chromatography term that corresponds to each definition.
The substance that carries the components of a mixture
Choose...mobile phase
A value that quantifies the distance traveled by a substance relative to the
distance traveled by the solvent
Choose...Rf
The substance to which the sample is bound at the start of an experiment
Choose...stationary phase
A method used to separate components of a mixture
Choose...chromatography - ANS✔✔-Be sure to review all terms associated with
chromatography prior to starting the procedure. In order for a chromatography
experiment to work, it is necessary to pay careful attention to each variable in
the experiment.
Aspirin is usually packaged with
Choose...buffering agent to reduce its
