객관식
Which principle allows chromatography to separate the components of a mixture?
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4. BONUS: Lab Techniques and Procedures
Chromatography
객관식
Which of the following best describes how thin layer chromatography (TLC) can be used to aid in the identification of a compound?
A
By determining the compound's solubility in water using the TLC plate.
B
By measuring the boiling point of the compound after separation.
C
By observing the color change of the compound when exposed to UV light before chromatography.
D
By comparing the R_f value of the unknown compound to the R_f values of known standards under the same conditions.
검증된 단계별 안내1
Understand that Thin Layer Chromatography (TLC) is a technique used to separate components of a mixture based on their different affinities for the stationary phase (the TLC plate) and the mobile phase (the solvent).
Recognize that each compound travels a certain distance up the TLC plate depending on its polarity and interaction with the solvent and stationary phase, which is quantified by the retention factor, \(R_f\).
Calculate the \(R_f\) value for a compound using the formula: \(R_f = \frac{\text{distance traveled by the compound}}{\text{distance traveled by the solvent front}}\).
Use the \(R_f\) values as a characteristic property of compounds under specific conditions, meaning that compounds with the same \(R_f\) value under identical conditions are likely the same substance.
Compare the \(R_f\) value of the unknown compound to the \(R_f\) values of known standards run on the same TLC plate with the same solvent system to aid in identification.
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