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Cards In This Set
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Why is TLC used?
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Used for rapid separation and qualitative analysis of small amounts of material
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What are the advantages of TLC?
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It is an extremely convenient method; that is fast, reproducible and uses only a small amount of sample (1-100 ug)
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What types of compounds does TLC not work with?
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Volatile compounds
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What chemical principle is TLC based upon?
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It is based on the relative degree of partition of compounds between the given moving liquid phase and the solid stationary phase
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What are examples of solid stationary phases?
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Silica gel or alumina
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What is a general overview of this experiment?
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1) Solid phase is spread out in a thin layer on a glass plate or plastic sheet.
2) Small amount of compound under investigation
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What is a general overview of this experiment?
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Dissolved in volatile solvent is spotted on one end of the plate and when the solvent
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What is a general overview of this experiment?
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Evaporates the compound becomes adsorbed onto the solid phase
Degree of adsorption depends on structure of compound
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What is a general overview of this experiment?
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3) Plate is then dipped into a shallow pool of developing solvent that will move up the plate by capillary action
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What is a general overview of this experiment?
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4) The compound that was spotted on the plate is attracted to the moving liquid phase and will move with it.
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What is a general overview of this experiment?
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Different compounds move up to different heights depending on their structure.
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Which type of substances will advance the farthest through capillary action?
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Generally the least polar substances will advance further than more polar
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Which type of substances will advance the farthest through capillary action?
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Substances since liquid phase is usually less polar than the stationary phase
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Which type of substances will advance the farthest through capillary action?
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Basically. Like attracts like.
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What are Rf values
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It is the distance travelled by the compound divided by the distance traveled by the solvent front.
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