Paper Chromatography Lab
Pre Lab:
Lab objective: Create a process for separating a mixture, specifically an ink mixture.
1. What colors are mixtures?
Orange ( red + yellow), Green (blue + yellow), Purple (red + blue), Pink ( red + white), Grey (black + white)
2. What substances could be used to separate a mixture?
Water, alcohol, bleach, acetone, nail polish, vinegar, ammonia, ethanol, peroxide.
3. What is paper chromatography?
Paper chromatography is an analytical method technique for separating and identifying mixtures that are or can be colored, especially pigments.
What is the set Paper Chromatography?
In the picture, the alcohol is in the cup. The strip of paper with the dot is in the alcohol. We were waiting for the results.
Hypothesis Questions:
1. Are colors mixed to make other colors?
Yes, colors are mixed to make other colors. For example, to make grey, you would have to use black and white.
2. Can mixed colors separate into their components colors?
Mixed colors can separate into their components colors
3. Can black separate into it's component colors?
No
4. Which colors will separate out?
Blue, red, orange.
Materials:
Goggles
Black marker
Strips of filter paper
Metric ruler
Plastic cup
Rubbing alcohol
Tape
Pencil
Procedure:
1. Use the marking pen to draw a horizontal line across the width of a strip of filter paper, 2 cm from one end of the strip.
2. Tape the unmarked end of the filter paper to the center of a pencil so that the strip hangs down when the pencil is held horizontally.
3. Working in a well-ventilated room, pour rubbing alcohol into a plastic cup to a depth of 1 cm.
4. Rest the pencil on the rim of the cup so that the end of the paper strip with the ink mark is just barely in contact with the rubbing alcohol.
5. Observe for 15 minutes.
6. If time permits, repeat this lab using different brands and different colors of pens. Also, try using water in place of rubbing alcohol.
Data table:
Observation
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Observation at 3 minutes
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Observation at 6 minutes
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Dry test strips
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Expo marker with alcohol
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The alcohol touched the dot
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The alcohol passed the dot
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The black expo marker didn't separate
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Expo marker with other solutions
(Acetone)
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The color started to rise
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The color started to rise even more
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The dot smeared and looks smudged, it looked sort of grey
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The expo marker with water
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The water risen up. The water touched the black dot
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The water risen up to almost the whole strip almost
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Didn't separate
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| This is a picture of our test while it was running. |
Analysis and Conclusion:
1. What appeared on the filter paper? Describe all results
The colors did not separate. For the alcohol strip, the alcohol looked as though it was trying to separate but there were no colors showing at all. For water, there was no results.
2. What did the results indicate about the black ink?
The results indicated that the black ink is homogeneous mixture. A grey sort of color came out of the black dot.
3. Is chromatography a useful separation method for ink mixtures? Explain based on your results.
Chromatography is a a useful separation method for ink mixtures. At first I didn't think that chromatography wasn't a good separation method for ink mixtures based on my results. Then, I came to the conclusion that we had to change the solution. It wasn't the method itself, the solution wasn't strong enough so we changed the solution, and the method worked.
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 to test another condition or factor, I would want to test a permanent marker like a sharpie. I would like to see what colors would separate out.
Post Lab:
How does paper chromatography work? What do the results tell us?
Preferential absorption of chemical compounds (gas or liquid) in an ascending molecular weight sequence.
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