General Chemistry 1025c Mixtures Vs Pure Substances Using Chromatography For Separation Lab-Sl (Page 2 of 2) in pdf

2. Place small dots of ink from 6 different pens at the marks on the paper. Immediately make a record of

which pens you used. For example, note, that Dot 1 from the left is Pen Color Blue Type Vis-à-vis.

3. Place the straw over the top of the beaker. Do not use the spout as a resting area for the straw, as this

will cause your paper to be slanted, and your colors to run together. Fold or roll the top of edge of the paper

so that it hangs on the straw rod inside the beaker. Make sure the bottom of the paper does NOT touch the

bottom of the beaker. Make sure the paper hangs evenly in the beaker. This will ensure that the solvent

travels evenly up the paper.

4. Add a small amount of distilled water so that there is a shallow pool of pure water in the beaker with the

bottom of the paper extending into it. Leave the beaker undisturbed on the lab bench and observe what

happens.

5. When the top edge of the water has moved about 2/3 of the way up the paper, remove the paper and

prop it up against the beaker to dry. Also mark the top edge of the wet area (where the water moved to) with

your pencil.

6. Remove the water from the beaker and let the paper dry on the straw in the dry beaker. Watch the colors

emerge as the paper dries.

6. When the paper is completely dry, staple it to a sheet of plain white computer paper. Label it with your

name, your partner’s name, the date, and what each dot represented.

7. Answer the questions below.

Questions are to be answered on separate sheet of paper.

1. Which of the pen inks appear to contain a single colored substance, and which are mixtures? Describe the

evidence you have to support your conclusion.

2. Which pens have colored components in common with other pens? Explain your reasoning.

3. From your results, predict which colored components are most soluble in water and which are least soluble

in water. Explain your reasoning.

4. Describe an experiment you could do in your kitchen to convince a friend that the hard coating on an M&M

contains a mixture of several food colorings. Explain what you would do and what you would see as results.

5. What do you think would happen if you repeated the experiment with non-washable (permanent) markers

such as Sharpies?

6. Investigate: What type of liquid solvent do you think would be good to use in the separation of inks of

permanent markers such as Sharpies?

7. Watch the video clip on at the following weblink:

Report what you see in the clip. Your report should include the solvent used, the color of the marker used,

and the separation observed. How did this separation differ from the separation you performed in lab?

8. Investigate: Research other types of chromatographic methods of separation. Write a short paragraph

(minimum 8 sentences) on one other type of chromatographic separation method. Include in your discussion

when this method is most commonly applied. Cite your source.

Instructor’s Initials:________________________________________

General Chemistry 1025c Mixtures Vs Pure Substances Using Chromatography For Separation Lab-Sl Page 2