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Well it depends on the solvent you are using, but lets assume you use pentane as the solvent for fluorene and diethyl ether as the solvent for fluorenone. Used in this order, fluorene should actaully move slower down the column due to the the polarity of the alumina and the nonpolarity of the solvent (pentane). Since fluorene is less polar so, remember the rule like dissolves like? Well, this kind of applies to chromatography wherein rather than dissolve just replace it with moves with, so like moves with like. That being said the pentane will "carry" the fluorene through the alumina slower than the latter (which I will explain). Fluorenone is polar because of its C=O bond, that being said the dielectric constant of diethyl ether is 4.3 which means it has intermediate polarity (remember that pentane has a dielectric constant of 2.1 I think, so it is nonpolar). Since the alumina, diethyl ether, and the fluorenone are all polar, the fluorenone will travel faster through the alumina than would the fluorene, because there is no attraction between all these polar compounds which will allow it to move faster, rather than a nonpolar and polar chemical having an attration towards each other and thus moving more slowly.
Hope this helps,
Branden
What else can I help you with?
What is the difference between flash chromatography and column chromatography?
Column chromatography, is a broad term for all column chromatography methods, but is also synonomous with Gravity fed methods. Flash chromotography refers specifically to a column in which the eluant (or mobile phase) is moved through the column under pressure (using a hand pump for small scale, or a pressurised gas for a larger scale), the name Flash is derived from how much faster it is to run a column under pressure than via gravity.
What is the difference between vacuum chromatography and flash chromatography?
Flash chromatography uses pressure (under 10 psi) to pump solvent down a column at a rate faster than gravity would provide. Vacuum chromatography uses a vacuum at the bottom of the column to pull solvent through. Both can be performed with standard glass columns, but usually vacuum chromatography is done with a silica filled vacuum funnel instead as a rough purification technique.
Why the descending method of chromatography is faster than the other method?
Descending chromatography is faster because gravity aids in pulling the solvent down through the stationary phase, allowing for quicker elution of compounds. In this method, the analytes travel with the solvent flow, resulting in faster separation compared to ascending chromatography where the solvent has to move against gravity.
What is molecular exclusion chromatography?
Molecular exclusion chromatography is a type of size exclusion chromatography that separates molecules based on their size and shape. It works by passing a sample mixture through a porous stationary phase, where smaller molecules are able to enter the pores and take longer to elute, while larger molecules pass more easily through the column and elute faster. This technique is commonly used for separating proteins and nucleic acids.
Which of the compounds elute fast in reverse phase chromatography?
Compounds that are non-polar elute faster in reverse phase chromatography as the stationary phase is non-polar and retains polar compounds longer. Polarity of the compound determines its retention time in reverse phase chromatography.
What are the Advantages of column chromatography over thin layer chromatography?
One is faster and more flexible, the other is a bit heavier
What is the difference between flash chromatography and column chromatography?
Column chromatography, is a broad term for all column chromatography methods, but is also synonomous with Gravity fed methods. Flash chromotography refers specifically to a column in which the eluant (or mobile phase) is moved through the column under pressure (using a hand pump for small scale, or a pressurised gas for a larger scale), the name Flash is derived from how much faster it is to run a column under pressure than via gravity.
What is the difference between vacuum chromatography and flash chromatography?
Flash chromatography uses pressure (under 10 psi) to pump solvent down a column at a rate faster than gravity would provide. Vacuum chromatography uses a vacuum at the bottom of the column to pull solvent through. Both can be performed with standard glass columns, but usually vacuum chromatography is done with a silica filled vacuum funnel instead as a rough purification technique.
How do hetp units contribute to the efficiency of the separation process in chromatography?
HETP units, or Height Equivalent to a Theoretical Plate units, contribute to the efficiency of the separation process in chromatography by measuring the effectiveness of the column in separating compounds. A lower HETP value indicates better separation efficiency, as it means that the column can separate compounds more effectively in a shorter distance. This leads to faster and more accurate separations in chromatography.
Why the descending method of chromatography is faster than the other method?
Descending chromatography is faster because gravity aids in pulling the solvent down through the stationary phase, allowing for quicker elution of compounds. In this method, the analytes travel with the solvent flow, resulting in faster separation compared to ascending chromatography where the solvent has to move against gravity.
What are the advantages and limitations of column chromatography over thin layer chromatography?
TLC. The mobile phase is a liquid, the stationary phase is a solid. Useful for seperating and comparing mobility of solids and some liquids dissolved in the mobile phase by their affinities to the solid phase relative to the mobile phase. GLC. The mobile phase ia s gas, the stationary phase is a liquid on a solid support. same concept as TLC. useful for seperating gases by their affinities to the stationary phase...the mobility can then be compared to known compounds for possible identification.
What is molecular exclusion chromatography?
Molecular exclusion chromatography is a type of size exclusion chromatography that separates molecules based on their size and shape. It works by passing a sample mixture through a porous stationary phase, where smaller molecules are able to enter the pores and take longer to elute, while larger molecules pass more easily through the column and elute faster. This technique is commonly used for separating proteins and nucleic acids.
Which of the compounds elute fast in reverse phase chromatography?
Compounds that are non-polar elute faster in reverse phase chromatography as the stationary phase is non-polar and retains polar compounds longer. Polarity of the compound determines its retention time in reverse phase chromatography.
Formula for calculating distribution coefficient kd in size exclusion chromatography?
The distribution coefficient, Kd, in size exclusion chromatography is calculated using the equation Kd = Vt/Vo, where Vt is the total elution volume of the sample and Vo is the void volume of the column. The distribution coefficient provides information about how the sample components interact with the column matrix based on their size and shape, with larger molecules eluting faster than smaller ones.
What are the avantages of thin layer chromatography over paper chromatography?
Thin layer chromatography typically provides better resolution and separation of compounds due to the use of a uniform, inert stationary phase. It also offers faster separation times and requires smaller sample volumes compared to paper chromatography. Additionally, thin layer chromatography allows for visualization of separated compounds under UV light without the need for chemical staining.
What would have been the result if a large quantity of petroleum ether alone were used as the eluent in either of the experiments described in column chromatography?
petroleum ether is a lot less polar than solvents like MTBE and the hexanes. so if the stationary phase is a lot more polar than the solvent then the components of the mixture that were added to the column to be separated will get stuck in the stationary phase
What are the key differences between paper chromatography and thin layer chromatography?
Paper chromatography and thin layer chromatography are both techniques used to separate and analyze mixtures of substances. The key differences between them lie in the materials used and the method of separation. In paper chromatography, a strip of paper is used as the stationary phase, while in thin layer chromatography, a thin layer of silica gel or other material is used. Additionally, in paper chromatography, the solvent moves up the paper through capillary action, while in thin layer chromatography, the solvent is applied directly to the stationary phase. Overall, thin layer chromatography is faster and more efficient than paper chromatography, but both techniques have their own advantages and applications in analytical chemistry.
