What effect will the following factors have on a column chromatographic separation with alumina as the...
What effect will the following factors have on a column chromatographic separation with alumina as the stationary phase?
A) methanol is used as the initial eluting solvent
B) The level of the eluting solvent falls below the top of the column?
C) Heptane is used as the initial eluting solvent
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What effect will the following factors have on a column
chromatographic separation with alumina as the...
What effect will the following factors have on a chromatographic separation: too strong an adsorbent; a...
What effect will the following factors have on a chromatographic separation: too strong an adsorbent; a collection of large elution fractions; solvent level below the top of column adsorbent?
Question 1: (column chromatography) a. What effect on the chromatographic separation is expected ...
Question 1: (column chromatography) a. What effect on the chromatographic separation is expected if solvent level is below the adsorbent? b. Once the chromatographic column was prepared, why was it important to allow the level of the liquid in the column to drop to the level of the stationary phase before applying the solution of the compounds to be separated? c. Name two methods of carrying out the column chromatography technique? d. What are the two methods of packing a...
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In a chromatographic separation of two components A and B. Component A has a value of...
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Question 1 Which of the following is the advantage of straight packed column? Selected Answer: It can be repacked easily Answers It can be packed uniformly It can be repacked easily It is compact It is easier to heat it evenly Question 2 Which of the following statements most accurately describes thin-layer chromatography? Selected Answer: technique used to separate non-volatile mixtures, the mobile phase has different properties from the stationary phase. Answers The mobile phase is the solvent also called...
Consider a separation performed on a 45.0 mm long open tubular column with a 0.50 mm...
Consider a separation performed on a 45.0 mm long open tubular column with a 0.50 mm diameter, and a 2.0 um thick stationary phase. Compound A eluted at 12.41 min, compound B eluted at 13.34 min, and the unretained solvent eluted at 1.130 min. What are the adjusted retention times, t, and retention factors, k, for compounds A and B? Number Number min Number Number min rB What is the relative retention, a, for this separation? Number roll down to...
1. What is the retention factor for the following TLC plate if the baseline is 1...
1. What is the retention factor for the following TLC plate if the baseline is 1 cm, elute solvent traveled 5cm, and the spot of interest traveled 2.5cm? a) 0.50 b) 1.6 c) 0.63 d) 1.4 10. Column chromatography employs both a stationary and a mobile phase. Which of the compounds listed below is commonly used as the stationary phase in column chromatography? a) decolonizing charcoal b) sodium bicarbonate c) benzoic acid d) silica gel
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Acetylation of ferrocene and column chromatography
Lab 4: Question 3 Homework • Unanswered Important ... The solvent is changed from petroleum ether to diethyl ether after the ferrocene is collected from the column. Why not use diethyl ether the entire time? Because diethyl ether is more polar than petroleum ether Because petroleum ether selectively elutes ferrocene since it contains more ether oxygens than diethyl ether Because diethyl ether would lead to a poorer separation of ferrocene and acetylferrocene Both a...
1. which of the following are not absorbent for TLC? a. magnesium silicate b. polyamides c....
1. which of the following are not absorbent for TLC? a. magnesium silicate b. polyamides c. silica gel-F ( fluorescing indicator added) d. starch e. alumina f. none of the above 2. select the best answer from the statements below about thin layer chromatography A. in normal phase thin layer chromatography the stationary phase is polar silica gel b. in normal phase thin layer chromatography the mobile phase is an organic solvent or a mixture of organic solvents Which is...
8.5 TLC is commonly employed with column chromatography to monitor the separation of colorless compounds. The...
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What is the main purpose of running a column chromatography? Similar to TLC. column chromatography is based on analytes being partitioned between a stationary phase (not moving) and a mobile phase (moving). What is most commonly used as stationary phase in a column? Is this material polar or non-polar? In this experiment, you will use different solvents to run column chromatography separation of different pigments extracted from spinach leaves. These solvents are a mixture of acetone and hexanes. (a) What...
Question 1 Which of the following is the advantage of straight packed column? Selected Answer: It can be repacked easily Answers It can be packed uniformly It can be repacked easily It is compact It is easier to heat it evenly Question 2 Which of the following statements most accurately describes thin-layer chromatography? Selected Answer: technique used to separate non-volatile mixtures, the mobile phase has different properties from the stationary phase. Answers The mobile phase is the solvent also called...
Consider a separation performed on a 45.0 mm long open tubular column with a 0.50 mm diameter, and a 2.0 um thick stationary phase. Compound A eluted at 12.41 min, compound B eluted at 13.34 min, and the unretained solvent eluted at 1.130 min. What are the adjusted retention times, t, and retention factors, k, for compounds A and B? Number Number min Number Number min rB What is the relative retention, a, for this separation? Number roll down to...
Acetylation of ferrocene and column chromatography
Lab 4: Question 3 Homework • Unanswered Important ... The solvent is changed from petroleum ether to diethyl ether after the ferrocene is collected from the column. Why not use diethyl ether the entire time? Because diethyl ether is more polar than petroleum ether Because petroleum ether selectively elutes ferrocene since it contains more ether oxygens than diethyl ether Because diethyl ether would lead to a poorer separation of ferrocene and acetylferrocene Both a...
8.5 TLC is commonly employed with column chromatography to monitor the separation of colorless compounds. The column is allowed to elute into many containers, usually test tubes. This is followed by a TLC on a long plate containing the same stationary phase as the column chromatography. Since a large number of tubes must be spotted, by spotting only every other (or every three etc.) tube on the plate. After visualization (by UV), the TLC plate is used to judge which...
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