Paper Chromatography Lab

Pre-Lab:

Lab Objective: Create a process for separating a mixture, specifically an ink mixture.

1. Colors of mixtures are pink (made up of white and red), purple (made up of blue and red), green (made up of blue and yellow) and many more.

2. Mixtures can be separated with the help of substances such as bleach, alcohol and water. 

Hypothesis Questions

1. Are colors mixed to make other colors?

   -Yes. Many colors are made up of other colors such as orange (made up of yellow and red), blue (made        up of green and yellow) and so on.

2. Can mixed colors separate into their components' colors?

   -Yes. Mixed colors can separate into their components' colors using paper chromatography.

3. Can black separate into it's components' colors? Which colors separate out?

   -Yes. Yellow red and blue will separate out because when mixed together, they make black.

Paper Chromatography

1. What is paper chromatography?

   -Chromatography is a method for analyzing complex mixtures (such as ink) by separating them into the           chemicals from which they are made. This is done by separating some property that distinguishes the             components such as their relative: size, density, solubility, and electrical charge. 

2. Set up for paper chromatography:

3. Materials:
   -Goggles, green and black markers, strips of filter papers, metric rulers, plastic cups, rubbing alcohol, tape,      and pencils.

4. Procedure:

1.Using the ruler, cut the filter paper into long, rectangular strips, about 3 cm x 10cm. *You need 2*

2.Measure 0.5 cm from the bottom of the paper strip and draw a horizontal line with your pencil across the width of the strip. Then, use the black marker to make a dot on the pencil line.

3.Tape the paper strip around the pencil so that the very bottom of the strip touches the alcohol.

**Do not let ink dot touch alcohol

4. Pour rubbing alcohol into a plastic cup to a depth of ½ cm. Then, rest the pencil on the rim of the cup so that the end of the pencil strip with the ink mark is just barely in contact with the alcohol.

5. Observe for about 8 minutes.

6. Let the strip dry by taping it to a piece of paper provided.  Put group names, period, and ipod # on the sheet.

7. Repeat the process for the other solution for the same marker.

Data Table:

Observations	Observation at 3 minutes	Observation at 6 minutes	Dry test strips
Black sharpie marker w/ alcohol	The ink begins to rise with the solvent and a dark purple color begins to show	The ink still rises with the solvent. The ink slowly begins to show a true purple and blue color	The ink from the shaprie marker still shows blue and purple colors
Black marker with bleach	Nothing happens to the ink. The bleach solvent travels slower than the water but faster than the alcohol, through the paper, leaving the ink unaffected	Still nothing occuring	The bottom of the actual test strip was faded in color. The sharpie ink was still unaffected.
Black marker w/ H2O	The water solvent traveled through the filter paper fairly quickly but left the ink unaffected	Ink still unaffected	The test strip was wrinkly and shriveled up while the sharpie ink was still unaffected.

Analysis and Conclusions

1. What appeared on the filter paper? Describe all results. 

   -Water: None of the sharpie inks components were exposed while using water as a solvent. Reason being,     the sharpie marker is permanent which means it is hydrophobic-not easily dissolved in water. 

   -Alcohol: The components of the sharpie ink spread out and rose with the alcohol solvent during my test.       This is because the sharpie marker is alcohol based, moreover, alcohol contains polar molecules-                   molecules with a positive charged molecule that sticks to a negative charged molecule. When alcohol is         added to the sharpie ink, the two polar solvents follow the "like dissolves like" rule which is a rule                   that states that polar solvents with dissolve polar solutes and non-polar solvents will dissolve non-polar         solutes.

   -Bleach: Nothing happened to the sharpie ink when bleach mixed with water was used as a solvent. I'm         assuming because of the fact that water was added into the mixture which did not affect the sharpie ink. 

2. What did the results indicate about the black ink? What classification of matter could you give the ink?

    -My results from my tests proved that the sharpie marker is a homogeneous mixture and not a substance.        Only one phase is presented when the sharpie marker is left unaltered but it's components can be                  separated and exposed. 

3. Is chromatography is useful separation for ink mixtures? Explain based on your results.

    -I think it is a useful technique. The alcohol separated the ink well during my lab. The results depend on          the solvent used. 

4. If you could alter the experiment to test another condition or factor, what would you change or test?

    -If I could alter the experiment, I would leave the filter paper in the alcohol solvent to see further results. I      would also test with different solvents.

Post Lab

How does paper chromatography work?  What do the results tell us? 

A: Preferential adsorption of chemical compounds (gases or liquids) in an ascending molecular-weight sequence.