Chromatography Key-
1. State your conclusions to this experiment. Be sure to support your analysis with data from the experiment. Explain which colors were mixtures or pure substances and why.
The black ink was obviously a mixture. I know that the black ink was a mixture because during the chromatography the black ink separated into several different colors- showing that it was a mixture a 3-4 different substances. The brown ink was also a mixture because it separated into several different colors during the experiment. Some blue inks did separate indicating that they were mixtures but some blue inks did not. The Green and purple inks were pure substances because they did not separate out during the chromatography- showing that they were only made of one type of substance. The red ink is tricky. It appears to be a pure substance but if you look really closely- you will notice that there are actually two slightly different colors- indicating that it is a mixture.
2. Identify the solution, the solvent & the solute.
The solution is made of the ink and the water with the ink as the solute and the water as the solvent.
3. Explain how chromatography works.
Chromatography is a physical method used to separate mixtures. This is accomplished by using a filter with a solvent moving through it. The mixture is the solvent. As the solute moves through the filter it will move the substance with it. However- if the substance is a mixture and made of different substances- each substance will move on at a different rate along the filter. For example- if one substance is made of a large molecule it will move through the filter very slowly while a substance made of a small molecule will move very quickly – causing the mixture to separate.
4. Were the mixtures homogeneous or heterogeneous? Explain why.
All of the inks that are mixtures are homogeneous mixtures because they are consistent throughout- until you separated the colors using chromatography you could not tell that it was a mixture because the mixture was evenly distributed.
5. Did this lab use physical or chemical properties? Explain how you know and state the properties.
This chromatography lab uses primarily physical properties to separate the ink. There were two methods of separation occurring. The first method involved the solubility of the ink. If the mixture was made of two or more substances with varying solubility in water then the substance that was most soluble would separate out first. The second method is particle size. The filter paper acts like a filter and prevents larger molecules from moving as quickly as smaller molecules- so the smaller molecules move up the paper with the water faster than the larger particles.