Pre Lab

Shakira Cruz
Chemistry                                               
H- 23

Paper Chromatography

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

1.) What colors are mixtures?

· Orange (red and yellow), Green (Blue and yellow), Grey, Black.

2.) What substances could be used to separate a mixture?

· Water, alcohol, bleach (chlorine), acetone, nail polish,

· vinegar, ammonia, ethanol, hydrogen 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.

Materials Used for Lab Experiment:

• Goggles
• black markers
• strips of filter
• Tape
• cups
• ruler
• solvent
• scissors

 

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 end of the paper strip with the ink mark is just barely in contact with the rubbing alcohol. Carefully cover the top of the cup with plastic wrap.
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.

Questions/ Hypothesis

• Are colors mixed to make other colors? Yes, colors are mixed to make other colors.
• Can mixed colors separate into their component color? Yes, if you mix it with water, place the paper towel in the water and it will separate the colors.
• Can green and black separate into their component colors? I don't think so since black and green are both dark colors.
• Which color will separate out? I think only the light colors would separate out such as pink, blue, yellow, grey, orange and so on. Colors that are light and easy to mix.

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.

Data Table:

Observation	Observation at 3 min	Observation at 6 min	Dry Test Strips
Name black marker w/ alcohol	Water is rising and touched the black dot	Water keeps rising	Black marker dot did not separate
Black marker w/ other solution	Water raised up	Black marker dot began to separate	Black dot completely separated
Black marker w/ H2O	Touched the black dot	Water kept rising	Black dot remained in the same spot
Test Stripes after they are dry	Water the black dot remained the same	alcohol stood the same, went up a little not completely	acetone separated  completely.

Analysis and Conclusion

• What appeared on the filter paper? Describe all results: For the alcohol strip it looked like the color was going to separate but it didn't. For the water strip the black dot didn't separate at all.  Also the testing of the solvent (acetone) concluded the acetone separating.

• What did the results indicate about the black ink? What classification of matter could you give the ink?  The black ink didn't move for water or alcohol solvent. I'm thinking that we should change the solvent to a different one and see if it would separate if not then its the marker that has to be changed.  

• Is chromatography a useful separation method for ink mixtures? Explain based on your results.  Chromatography can be useful for ink mixtures only if it has a specific solvent, because based on my results the black dot didn't separate, but the other teams did. It could have been because of the solvent or the marker.

• If you could alter the experiment to test another condition or factor, what would you change or test? If I could test another experiment I would change the marker to a different marker and use a different solvent.  Maybe, acetone, to see if the marker dot would separate since its in a different solvent. 

 Post Lab:

  What is Chromatography?

 

 

How does paper chromatography work? What do the results tell us? Chromatography is a preferential adsorption of chemical compounds (gases or liquids) in an ascending molecular weight sequence.