Chromatography Lab

Sahomy Rodriguez                                                    October 16, 2013

    5th period                                                                     H-18

                Paper Chromatography Lab (Seperating Mixtures)

• Pre-Lab:

1. What colors are mixtures?

Pink is a mixture of red and white as green is also a mixture of green and yellow.

   2.  What substances could be use to separate a mixture?

Substance that can be used to separate a mixture is H20, oil, alcohol, and bleach.

   3.  What is Paper Chromatography?

Chromatography is a method for analyzing complex mixtures (such as ink) by separating them into the components from which they are made up of.

   4.  What is the set up for Paper Chromatography?

•  Hypothesis Questions:

1. Are colors mixed to make other colors?

Yes because colors such as purple is a mixture of blue and red.

   2.   Can mixed colors separate into their component colors?

Yes by using the method of paper chromatography.

   3.   Can black separate into it's component colors? Which colors will it separate out to?

I believe black can separate into it's component colors which most likely be gray, white, and primary colors such as red, yellow, and blue.

• Materials:

-Goggles  

-Green and Black Markers 

-Strips of Filter Papers

-Metric Ruler

-Plastic Cup 

-Rubbing Alcohol

-Tape 

-Pencil

• 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:

Observations	Observation at 3 minutes	Observation at 6 minutes	Dry test strips
(Sharpie) Black marker w/ alcohol	Ink is rising/fading.  Solvent is slowly rising.	Gray purple and blue is separating from the mixture.	The mixture faded into the component shades of gray, dark blue, and purple.
Black marker with bleach	Solvent is quickly rising.	Still no change.	No components rised.
Black marker w/ H2O	Nothing has happened no rising occurring.	Again, nothing. No difference.	The mixture sample stayed in the same condition with no visible components.

•  Analysis and Conclusion:

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

Alcohol Test - This test was the only that separated the black into a gray, purple, and blue.

Water Test - This substance did not separate the mixture at all.

Bleach Test - The black did not separate with bleach either.

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

The results indicated that the black ink is made up of different colors which absorb wavelengths and reflect others and this makes it evident that the black does not reflect anything. The ink is classified as a liquid and does not separate with every solvent. Therefore the sharpie marker's ink would be classified as not water-soluble which means it can't be dissolved in water. (Sources= http://www.sciencefriday.com , http://www.scientiareview.org/pdfs/167.pdf)

   3.  Is chromatography a useful separation method for separating ink mixtures? Explain based on your results.

Based on my results chromatography is a useful method for separating ink mixtures. Chromatography is a easy way to separate ink mixtures as I did with a black dot of a sharpie marker and alcohol. This solvent separated the mixture rapidly.

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

If I was able to alter the experiment I would've let the filter paper in each solvent in longer so all the components can show through adsorption and with more time the mixture on the filter paper in bleach would've separated.

• Post Lab:

1. 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.