Paper Chromatography

Britney Montalvo                                                   October 22, 2014

H:18                                                                 5th Chemistry*                     
                                  Paper  Chromatography 
                                   (Separating Mixtures)
Pre-lab:
Lab objective: create a process for separating a mixture, specifically an ink mixture.

What colors are mixtures?

• pink
• red
• orange
• green

What substances could be used to separate mixtures?

• rubbing alcohol
• vinegar 
• water
• hydrogen peroxide 

What is paper chromatography?
 Paper chromatography is the separating and identifying of mixtures that are colored. The image below is a picture of paper chromatography.

 

Separating the

Components of a Mixture

Most laboratory work in biology and chemistry requires the use of techniques to separate the components of mixtures.

Hypothesis Questions                                                                           1. Can green separate into its component colors? If yes, then which will separate out?                                                                                  Yes, it will change into its component colors. Those colors are yellow and blue.                                                                       

2. Can black separate into its component colors? If yes, then which colors will separate out?                                                                      Yes, black will change into its component colors because black

is a mixture of all colors.   

Materials                                                                                             

• Goggles                                                                                  
• Green and black marker                                                         
• Strips of Filter Papers    
• Metric Ruler
• Plastic Cup
• Rubbing Alcohol
• Tape
• Pencil

Procedures

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	Obs at 3 min	Obs at 6 min	Dry test strips	Rf
black dye w/ alcohol	The color did not go all the way up, it was blue.	Started to rise but then faded away into a blue color	You could see the results a lot more. You could see blue and green and some yellow.	3 1/2
Black dye with other solution	Started rising up the paper faster than  it did with alcohol and saw more color	It went all the way up to the top and could see more color.	The dye stayed at the top and when it was dried completely it was much more colorful	6 1/2
Green dye w/ alcohol	Went up half way and turned a light baby blue color	It stopped going up the paper and the color remained blue	The color stayed blue and did not move, it stayed the same	3 1/2
Green dye with other solution	The dye went up faster with water it went up about 4cm	It rose up 2cm and still had a lot of color	Increased in color	6 1/2

Red with vinegar	went up slowly and had some color	color is only 2cm	no major changes made	6 1/2
Green with vinegar	color is 1cm	went up slowly	no change made	3

Equation for the Data Table:

Post Lab Questions:

1.) What did the results indicate about the black ink? *What classification of matter (mixture, substance) could you give the ink?

• With the black ink in alcohol barely moved but in the water it went to the top of the filter paper very fast, the ink to me is a mixture because you can see all of the colors that make up black. (every color)

2.) What does the Rf value tell you about the solubility of a separated component (black ink) in the mobile phase solvent?

• It shows me that it would most likely go up at a faster rate, than the mixture

3.) Which mobile phase solvent worked best in the chromatography experiment?

• Capillary Action

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

• I would change the type of dye I used, to see what the difference would be.

Post Lab

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

• Paper chromatography works because of the solubility of the substance or mixture, and using capillary action.
• The results tell us that without capillary action and solubility of something chromatography would not work.

Resources
https://docs.google.com/presentation/d/1FdRZM_JjpEfLAQQX0MG786g8DVzXWVdtPv8TppG2v_g/edit#slide=id.g11c50f02a_011