Question
Plates used in this laboratory technique consist of a layer of silica on top of glass. For 10 points each:
[10h] Name this technique for monitoring the progress of reactions. A mixture of ethyl acetate and hexanes is used in this technique to transport compounds via capillary action.
ANSWER: thin-layer chromatography [or TLC; prompt on chromatography]
[10e] Visualization of TLC plates occurs under light from this region of the electromagnetic spectrum. On Earth, protection against this kind of light is provided by the ozone layer.
ANSWER: ultraviolet light [or UV light]
[10m] Spots on TLC plates are assigned one of these values. This value, which is also calculated in paper chromatography, is the distance traveled by the sample divided by the distance traveled by the solvent.
ANSWER: retardation factor [accept retention factor or Rf (“R-F”) or R-sub-f]
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