1) In a column chromatography procedure, if two compounds were eluted in the same fraction, how...
1) In a column chromatography procedure, if two compounds were eluted in the same fraction, how would you separate them?
2) why is it important to not let the column dry out?
Homework Answers
1. If the two compounds were eluted in the same fraction during column chromatography they have too similar retention factors in the given solvent sytem used to separate. We can try mixture of two different solvents starting with a less polar solvent such as petroleum ether and then mix it with different more polar solvent. Further, while packing column larger silica weight to sample weight should be used.
2. It is important to not let the column dry out, because if the column run dry the silica will crack resulting in a poor separation results. Infact, the solvent should never go below the level of the silica gel or poor results will be obtained.
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1) In a column chromatography procedure, if two compounds were
eluted in the same fraction, how...
4. You plan to separate a mixture of the two compounds below using a column chromatography...
4. You plan to separate a mixture of the two compounds below using a column chromatography normal conditions, which of the compounds would you expect to be eluted off the column first? Expla
Product fraction Submitted (attach to report) Structures of Chromatography Fractions: (Hexane-eluted Product) (Acetone-eluted Product) color clear...
Product fraction Submitted (attach to report) Structures of Chromatography Fractions: (Hexane-eluted Product) (Acetone-eluted Product) color clear Color Yellow Mass Isolated (g) 0.177g Mass Isolated 0.35g m. p. (degree C)114.7c/116.5C (lit. value_) m. p. (degree C) 81.4C-/89.9c (lit. value_ Calculations: Mass of mixture applied to column (g) 0. 48 % Composition of Starting Mixture (show calculation) % (Mass) Recovery (show calculation) _% of Starting Mixture Recovered Questions: What is the maximum possible % recovery, and why would you not expect to...
Chromatography I Questions Name CHE 201 Date The following solvent systems were found to separate compounds...
Chromatography I Questions Name CHE 201 Date The following solvent systems were found to separate compounds A and B by column chromatography: • A: hexane/ethyl acetate 10:1 • B: hexane/ethyl acetate 10:5 Which is the more polar compound, A or B? Explain your answer for credit, 2) In order to separate a mixture of A and B as in problem (1) by column chromatography: a. Which solvent system must be used first? Why? b. Which compound will elute from the...
Question 1: (column chromatography) a. What effect on the chromatographic separation is expected ...
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PART 1: In a gas chromatography experiment using a non-polar stationary phase A) solutes are eluted...
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2. An unknown compound was analyzed using thin layer chromatography, its constituted of two components (A...
2. An unknown compound was analyzed using thin layer chromatography, its constituted of two components (A and B) as shown in the TLC (Silica coated stationary phase; Chloroform and Ethyl acetate as mobile phase). The mixture was then loaded onto column with silica as the stationary phase and the same solvent system was used. (2 points) Column Chromatography TLC time A В Predict the order of elution of the compounds (A and B). which one would be eluted first/last and...
2. If two different compounds have the same Rr value, how might they be identified using paper chromatography?...
2. If two different compounds have the same Rr value, how might they be identified using paper chromatography? 3. Why is it important to keep the spots on the paper as small as possible? 4. If the solvent pool at the bottom of the beaker touched the spots on the 1.5cm line, what would happen to the spots? How would you address this error? 5. If you were teaching a student how to do paper chromatography, what three pieces of...
1. What is the purpose of column chromatography 2. What is the stationary phase? Mobile phase?...
1. What is the purpose of column chromatography 2. What is the stationary phase? Mobile phase? 3. What is the purpose of the cotton (glass wool) in column chromatography? 4. What is the purpose of the sand? 5. Why is it important to prevent the column from drying? 6. What can happen if you disrupt your even layer of silica gel? 7. Which compounds come off the column first, polar or nonpolar? 8. Keyon synthesized acetylferrocene (orange) in organic chemistry...
1mixture of luorene 1. Chromatography Concept. Draw and name the structures of the two substances in...
1mixture of luorene 1. Chromatography Concept. Draw and name the structures of the two substances in today's Cuoreron sample. Remembering that hexane will be the first eluent, and the stationary phase is alumina, which of these two substances should we expect to come out of the column first? Defend Si02 your answer [30pts] Al2O3 2. Equipment Practicals. In preparing the chromatography column, you were strongly advised prevent the stationary phase from drying. Suggest why you don't want the column to...
Ion Exchange Chromatography Experiment 1. What is the basis for the seperation of different compounds by...
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4. You plan to separate a mixture of the two compounds below using a column chromatography normal conditions, which of the compounds would you expect to be eluted off the column first? Expla
Product fraction Submitted (attach to report) Structures of Chromatography Fractions: (Hexane-eluted Product) (Acetone-eluted Product) color clear Color Yellow Mass Isolated (g) 0.177g Mass Isolated 0.35g m. p. (degree C)114.7c/116.5C (lit. value_) m. p. (degree C) 81.4C-/89.9c (lit. value_ Calculations: Mass of mixture applied to column (g) 0. 48 % Composition of Starting Mixture (show calculation) % (Mass) Recovery (show calculation) _% of Starting Mixture Recovered Questions: What is the maximum possible % recovery, and why would you not expect to...
Chromatography I Questions Name CHE 201 Date The following solvent systems were found to separate compounds A and B by column chromatography: • A: hexane/ethyl acetate 10:1 • B: hexane/ethyl acetate 10:5 Which is the more polar compound, A or B? Explain your answer for credit, 2) In order to separate a mixture of A and B as in problem (1) by column chromatography: a. Which solvent system must be used first? Why? b. Which compound will elute from the...
2. An unknown compound was analyzed using thin layer chromatography, its constituted of two components (A and B) as shown in the TLC (Silica coated stationary phase; Chloroform and Ethyl acetate as mobile phase). The mixture was then loaded onto column with silica as the stationary phase and the same solvent system was used. (2 points) Column Chromatography TLC time A В Predict the order of elution of the compounds (A and B). which one would be eluted first/last and...
2. If two different compounds have the same Rr value, how might they be identified using paper chromatography? 3. Why is it important to keep the spots on the paper as small as possible? 4. If the solvent pool at the bottom of the beaker touched the spots on the 1.5cm line, what would happen to the spots? How would you address this error? 5. If you were teaching a student how to do paper chromatography, what three pieces of...
1. What is the purpose of column chromatography 2. What is the stationary phase? Mobile phase? 3. What is the purpose of the cotton (glass wool) in column chromatography? 4. What is the purpose of the sand? 5. Why is it important to prevent the column from drying? 6. What can happen if you disrupt your even layer of silica gel? 7. Which compounds come off the column first, polar or nonpolar? 8. Keyon synthesized acetylferrocene (orange) in organic chemistry...
1mixture of luorene 1. Chromatography Concept. Draw and name the structures of the two substances in today's Cuoreron sample. Remembering that hexane will be the first eluent, and the stationary phase is alumina, which of these two substances should we expect to come out of the column first? Defend Si02 your answer [30pts] Al2O3 2. Equipment Practicals. In preparing the chromatography column, you were strongly advised prevent the stationary phase from drying. Suggest why you don't want the column to...
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