Purpose: To separate a mixture using paper chromatography.
Materials:
Green Marking Pen
Various marking Pens
Beaker
Pencil
Chromatography (filter) Paper
Metric Ruler
Clear Plastic Tape
Rubbing Alcohol
Procedures:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Obtain one pre- marked filter paper and two blank filter papers.
On the unmarked filter papers, draw a line across the bottom of the filter paper, 1 cm up from the bottom.
Trace the pencil line with the two different green pens/markers.
Tape the unmarked end of the filter paper to the pencil so that it hangs down vertically from the pencil,
when the pencil is held horizontally. (You may run two papers at one time.)
Carefully poor approximately ½ cm of rubbing alcohol into the bottom of the beaker.
Rest the pencil across the top of the beaker so that the bottom of the filter paper is barely beneath the
surface of the rubbing alcohol (don’t let the color line touch the alcohol).
Observe the changes in the strip of chromatography paper for 10 minutes.
Remove the filter paper from the beaker and immediately draw a line in pencil where the rubbing alcohol
has stopped as it has moved up the chromatography paper.
Make additional marks in pencil to locate the point at which each band of color has moved along the
chromatography paper.
Repeat steps 3 – 8 with each of the 2 unknowns your teacher has provided to you.
Observations: (Record at least 10 observations/questions)
Data: (Copy the following tables)
Data Table #1:
Green Pen
Unknown #1
Unknown #2
Distance Alcohol Traveled
Distance Alcohol Traveled
Distance Alcohol Traveled
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Distance
the color
traveled
Color
Band
Data Table #2:
Drawings of Ink Samples (You must show ALL colors)
Green Ink
Unknown
Sample #1
Unknown
Sample #2
Questions: (Answer in complete sentences.)
1.
2.
3.
4.
How did the appearance of the chromatography paper strips change in appearance during the procedure?
What evidence is there that any of the ink samples are mixtures? Explain.
Do either of the samples appear to be a pure substance? Why or why not?
Do either of your unknowns match your initial green ink sample? How do you know?
Conclusion (1 page): (Summarize this experiment and the results in complete sentences.)
Paragraph 1(Background/procedures): Include the name of the lab, the purpose of the lab, and a brief summary of the
procedures. Do not copy the listed procedures word for word. You do not need that much detail.
Paragraph 2(Data/results): Describe the data you collected from each of the 3 samples. Be sure to describe the color
bands for all samples and include specific numbers (distances) for at least one of the samples.
Paragraph 3(Analysis/conclusion): Explain what your data proved or showed in reference to the purpose of the lab.
Which sample matched your initial sample and how do you know? Were there any sources of error?