Chromatography??????

Question

At school we just recently did a chromatography experiment, the on with the pencil hanging down on some paper with a texta mark on it, and putting the tip of the paper into the water, making sure the dot does not touch the water.

We got the result of the mark separating colors and moving around, but I'm wondering how it works.

How did the water move up and separate the colors?

Why did the black mark separate into different colors such as blue?

What is th ink made from?

Why do different colors move different distances along the paper?

Answer 1

1.  As the paper soaks up the water, it dissolves the compounds in the mark you originally made.  Those compounds will then be carried up the paper as the water continues to move up.

2.  The black mark was a mixture of different dyes meaning there were other colors present in that ink.  

3.  Again, the ink was a mixture of different dyes.

4.  The reason why different colors move different distances on the paper has to do with how much attraction there is between the molecules of that particular color and the molecules of the water that is being absorbed.  If there is little attraction for the water, the color will move a long way up the paper.  If there is a high attraction for the water, the color will not travel very fast up the paper, they will stay close to the bottom.      

I hope this helps.  You might want to look at this website, it's about chromatography and it's really helpful.  

http://www.chemguide.co.uk/analysis/chro...

Answer 2

Chromatography (from Greek χρώμα:chroma, color and γραφειν:"graphein" to write) is the collective term for a family of laboratory techniques for the separation of mixtures. It involves passing a mixture dissolved in a "mobile phase" through a stationary phase, which separates the analyte to be measured from other molecules in the mixture and allows it to be isolated.

Chromatography may be preparative or analytical. Preparative chromatography seeks to separate the components of a mixture for further use (and is thus a form of purification). Analytical chromatography normally operates with smaller amounts of material and seeks to measure the relative proportions of analytes in a mixture. The two are not mutually exclusive.

Because molecules in ink and other mixtures have different characteristics (such as size and solubility), they travel at different speeds when pulled along a piece of paper by a solvent (in this case, water). For example, black ink contains several colours. When the water flows through a word written in black, the molecules of each one of the colours behave differently, resulting in a sort of “rainbow” effect.

     Many common inks are water soluble and spread apart into the component dyes using water as a solvent. If the ink you are testing does not spread out using water, it may be “permanent” ink. In such cases, you will have to use a different solvent such as rubbing alcohol.

Answer 3

Hi, we did the same at our school....

Obviously the colors seperated because the black colour is made out of other different colours and the water will seperate those colours.

Different colours used to make this ink moves up the paper as the water soak level rises it leaves different colours used to make this colour along the paper. Because molecules in ink and other mixtures have different characteristics (such as size and solubility), they travel at different speeds when pulled along a piece of paper by a solvent (in this case, water). For example, black ink contains several colours. When the water flows through a word written in black, the molecules of each one of the colours behave differently, resulting in a sort of “rainbow” effect.

     Many common inks are water soluble and spread apart into the component dyes using water as a solvent. If the ink you are testing does not spread out using water, it may be “permanent” ink. In such cases, you will have to use a different solvent such as rubbing alcohol