TLC exams and the correct answers 2034

In the thin-layer chromatography lab that you performed, what is the stationary phase? correct answersThe silica on the TLC plate In the thin-layer chromatography lab that you performed, what is the mobile phase? correct answersThe liquid solvent in the developing chamber In the thin-layer chromatography lab that you performed, what is the analyte? correct answersThe substance or mixture to be separated The distance a compound moves on a TLC plate is an indication of...? correct answersits polarity One can affect the distance a spot travels on a TLC plate by changing the... correct answerscomposition of the eluent If you allow a TLC plate to over-develop, causing the solvent front to reach the top of the plate, you cannot accurately determine... correct answers...the Rf values for your spots. For a given set of analytes, what effect would be observed if a non-polar stationary phase was used instead of a polar stationary phase? correct answersThe order of elution for the spots will be reversed with non-polar stationary phase. If you run a normal phase TLC plate and you find that all of your spots are at approximately the same Rf and near the bottom of the plate, what could you change to improve separation? correct answersChange to a more polar eluent. For a given analyte, which of the following eluents would give the largest Rf on a silica TLC plate? correct answers1:1 ratio of acetonitrile:water For a given analyte, which of the following eluents would give the largest Rf on a reverse-phase TLC plate? correct answers100% cyclohexane What analytes can be visualized under UV light on a TLC plate? correct answersCompounds that absorb UV light An analyte containing an amine functional group is found to have an Rf value of 0.65 on silica using a 2:1 ratio of petroleum ether:diethyl ether as the eluent. If a small quantity (0.5% by volume) of formic acid were added to the mobile phase, what would you expect the Rf for this analyte to be on silica under these conditions?