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Keeping a small spot on TLC will allow for greater resolution between the spots allowing for more accurate Rf calculations and solvent separation/preparation if used to isolate a compound in a mixture.

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OLIVIA YEO

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2y ago
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10y ago

If the spot is too big, they may overlap with other spots.

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11y ago

So that the solvent will not spread to other places and would only rise horizontally.

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10y ago

Because if they are too big, they will overlap one another. Thus we will not able to recognize the separation of the two components.

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8y ago

Because the colours look better like that when fater a bit

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10y ago

Really why? The reason is bc we don't want the dyes to mix with each other

I am a chemist major graduated from Cornell

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11y ago

to be sure that solvent is below it.

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Q: Paper chromatography Why must the spot be concentrated?
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What is The appearance of chromatograms in paper chromatography?

The chromatogram in paper chromatography is just the paper itself. You can look at the paper and see the dots that have risen due to the solvent. The appearance is just simply a piece of paper with dots that have risen from the baseline to a certain spot on the paper. see related link below for more info


What is meant by tailing a spot in Chromatography?

Chromatography is a method of analyzing the contents of a mixed substance. It is performed by dissolving the substance in a suitable solvent. A drop or spot of the resulting liquid is deposited near the edge of a piece of absorbent paper, such as blotting paper or special chromatography paper. The strip of paper with the spot at the bottom is then suspended over a solvent with the bottom edge of the paper in the solvent. As the solvent soaks upwards, the solvent carries some particles upwards and away from the spot. Different compounds within the mixture will travel at different rates and eventually the strip of paper will show different bands of colors, separating out and indicating some of the various components that were in the original substance. 'Trailing a spot' is a short term for this laboratory process.


Why stop paper chromatography from reaching the top of the paper?

The end of the paper nearest the spot is allowed to be in contact with a suitable solvent, WITHOUT immersing the spot itself. If the spots were immersed they would dissolve in the solvent and be pulled down into the solvent itself.


Does each spot on the developed chromatography paper or plate represent one substance?

That is correct. Every chemical substance travels at its own speed when diffusing through paper, and so every substance will wind up at its own location on the paper or plate as the case may be.


How do you use chromatography to show how many colors were in the solution?

It depends what sort of solution and what sort of chromatography. Assuming it's something simple like ink you'd usually use a piece of paper or filter paper. You'd apply a spot of your analyte (the solution being analysed) at a short distance from the bottom of the paper, then put the paper in a beaker or similar container with a small amount of ethanol, water or another solvent in the bottom. Ensure that the solvent does not go above the level of the spot of analyte. The solvent will be drawn up through the paper by capillary action, and will draw the different parts of the analyte with it and deposit them at different distances from the initial spot. Stop the experiment by removing the paper from the beaker once the solvent front (the horizontal line where the highest wet part of the paper is) reaches the top of the paper.

Related questions

How do you separate substances in red ink?

Chromatography should help. Spot ink onto absorbent paper, dip edge of paper in water, and wait.


What is The appearance of chromatograms in paper chromatography?

The chromatogram in paper chromatography is just the paper itself. You can look at the paper and see the dots that have risen due to the solvent. The appearance is just simply a piece of paper with dots that have risen from the baseline to a certain spot on the paper. see related link below for more info


What is meant by tailing a spot in Chromatography?

Chromatography is a method of analyzing the contents of a mixed substance. It is performed by dissolving the substance in a suitable solvent. A drop or spot of the resulting liquid is deposited near the edge of a piece of absorbent paper, such as blotting paper or special chromatography paper. The strip of paper with the spot at the bottom is then suspended over a solvent with the bottom edge of the paper in the solvent. As the solvent soaks upwards, the solvent carries some particles upwards and away from the spot. Different compounds within the mixture will travel at different rates and eventually the strip of paper will show different bands of colors, separating out and indicating some of the various components that were in the original substance. 'Trailing a spot' is a short term for this laboratory process.


Why stop paper chromatography from reaching the top of the paper?

The end of the paper nearest the spot is allowed to be in contact with a suitable solvent, WITHOUT immersing the spot itself. If the spots were immersed they would dissolve in the solvent and be pulled down into the solvent itself.


Does Rf means resolution factor in paper chromatography?

Rf is nothing but retardation factor in paper chromatography.Rf= distance spot traveled/distance solvent traveled


How are dyes and ink separated?

Dyes and inks are separated using a method called chromatography. Basically you put a dot of ink or the dye you to separate on a piece of chromatography paper and stand it up-right. The ink spot or dye will spread across the paper and separate into different colours.


Why can the pigment spot on chromatography paper not be submerged in solvent?

This is because the nonpolar pigments would just simply dissolve in the nonpolar solvent instead of traveling up the TLC plate.


Does each spot on the developed chromatography paper or plate represent one substance?

That is correct. Every chemical substance travels at its own speed when diffusing through paper, and so every substance will wind up at its own location on the paper or plate as the case may be.


How do you use chromatography to show how many colors were in the solution?

It depends what sort of solution and what sort of chromatography. Assuming it's something simple like ink you'd usually use a piece of paper or filter paper. You'd apply a spot of your analyte (the solution being analysed) at a short distance from the bottom of the paper, then put the paper in a beaker or similar container with a small amount of ethanol, water or another solvent in the bottom. Ensure that the solvent does not go above the level of the spot of analyte. The solvent will be drawn up through the paper by capillary action, and will draw the different parts of the analyte with it and deposit them at different distances from the initial spot. Stop the experiment by removing the paper from the beaker once the solvent front (the horizontal line where the highest wet part of the paper is) reaches the top of the paper.


How do you calculate Rf in chromatography?

In chromatography, Rf is the distance the solute travels divided by the distance the mobile phase travels. For example, in thin layer chromatography, if the spot travels 7 cm, and the mobile phase travels 15 cm, the Rf value for that spot will be 7/15 = 0.47


What does it mean if the spot is in the solvent front in chromatography?

it means that the solvent dissolves the solute.


What is the significance of Rf value in chromatography?

See related link below for a better explanation than mine.. I am not to familiar with Rf values, but I have an idea. Rf values are the ratio between the distance traveled by the spot of the analyte to the distance traveled by the solvent used. This is used in paper chromatography and thin layer chromatography. Rf value will allow you to compare to your unknown substance that you are trying to analyze. I will put a link the both paper and TL chromatography.