Cathy Dang
October 21, 2014
H18

                                                Paper Chromatography Lab  

Pre-Lab:

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

1.) What colors are mixtures?

Pink is a mixture; it is made of red and white. Green is also a mixture made of yellow and blue. Another mixture is purple, which is made of blue and purple. Furthermore, orange is a mixture made of red and yellow.

2.) What substances could be used to separate a mixture?
      Substances could be used to separate a mixture such as; alcohol, water, clear liquid soap, vinegar, hydrogen peroxide and nail polish remover. 

Paper Chromatography:
• Chromatography is a method for analyzing complex mixtures (such as ink) by separating them into the chemicals from which they are made.

Separating the Components of a Mixture
• Most laboratory work in biology and chemistry requires the use of techniques to separate the components of mixtures.

This is done by analyzing some property that distinguishes the components, such as their relative:

• size

• density

• solubility

• electrical charge

                                      

                                        

Hypothesis Questions:
1.) Can green separate into its component colors? If yes, then which colors will separate out?
Yes, green can separate into its components colors which are green and yellow. 

2.) Can black separate into its component colors? If yes, then which colors will separate out? 
No, black can not separate into its component colors. 

Materials

• Water

• Green and Black Markers

• Strips of Filter Papers

• Metric Ruler

• Plastic Cup

• Rubbing Alcohol

• Tape

• Pencil

Equation for the Data Table:

 

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 dye 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.

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 solutions of the black dye and green dye.

Observations	Obs at 3 min	Obs at 6 min	Dry test strips	Rf
black dye w/ alcohol	Different shades of lighter blue Solvent & component stopped at 3 minutes.	Nothing changed from 3 to 6 minutes.	Component looks exactly the same when dry.  No longer could see solvent.	1.5cm/ 2.3cm Rf = .7
Black dye with other solution (water)	Results were seen immediately. Light shade of red is the first color seen.	Red continues for about 4 minutes.  Red turns into blue.  Blue spreads yellow and green.  Black dye is no longer visible.  Continued after 6 minutes. Ends with blue. Solvent and component were close to each other.	Component looks exactly the same when dry.  No longer could see solvent	7cm/ 7cm Rf = 1
Green dye w/ alcohol	Extremely light yellow is shown. Yellow goes directly into a light shade of blue.  Solvent and component stopped at 3 minutes.	Nothing changed from 3 to 6 minutes.	Component looks exactly the same when dry.  No longer could see solvent	2.5cm/ 3cm Rf = .8
Green dye with other solution (water)	Light shade of yellow is the main color seen.	Light yellow eventually goes into blue after 4 minutes.  Continued after 6 minutes.  Ends with light shade of blue.	Component looks exactly the same when dry.  No longer could see solvent	6.6cm/ 7cm  Rf = .9

Test While Running

*Not my photo. We ran a test much like this, using only black and green dye. Instead of glass cups we used plastic. In addition, we used a pencil to hold up the filter paper.*

Dry Test Strips

Post Lab Questions:

1.The results indicated that the black ink is definitely a mixture; it can be separated into the components that made it. Although the results differ in component in water and alcohol, the black dye still displayed more than just black.

2. The results of the Rf told me that the black dye is more soluble in water than alcohol. The greater the Rf indicates the greater solubility. The results were the same with green dye; the greater Rf was with the green dye and water.

3.The mobile phase that worked best in the chromatography experiment is water. Both test strips with water have the higher Rf factor.

4. If I could alter the experiment to test another condition or factor, I would use another dye color as well. I would love to see how or if pink will separate into red and white on filter paper.

Sources:
www.yesmag.bc.ca/projects/paper_chroma.html

https://docs.google.com/presentation/d/1FdRZM_JjpEfLAQQX0MG786g8DVzXWVdtPv8TppG2v_g/edit#slide=id.g11c7b2c81_00 

Photo: http://www.birdandlittlebird.com/.a/6a00e550e99ce58834017744681b22970d-pi