Identifying Organic Compounds
Joe Harris 11/12/07
Organic compounds are, by definition, any chemical compound containing carbon. These compounds include carbohydrates, polysaccharides, lipids, proteins, and nucleic acids. Each one of these compounds has a different purpose. Carbohydrates give energy to cells when consumed. Lipids are basically the fats of a cell. Proteins are the building blocks of muscle in a cell. Nucleic acids are used to transfer genetic information from one cell to the other.
The purpose of this lab is to simply determine the absence or presence of the main chemical content of a given substance. In previous labs, there were tests with three chemicals, Lugol's solution, Benedict's solution, and Biuret solution. The tests were qualitative and tested for the presence of sugars, starches, or proteins within a given substance. The substances were already known, so the tests were used to figure out what each solution showed presence of. After going through all of the tests, Lugol's solution showed the presence of starch, Benedict's solution showed presence of sugar, and Biuret solution showed presence of protein. In this lab, these solutions will be put to the test.
2. Materials and Methods
The following materials are needed to complete this lab:
unknown substance A
unknown substance B
2 pipettes (one for each substance to avoid contamination)
2 test tubes
test tube tray/holder
1.Take one label per test tube and label one test tube “A” and one “B”.
2.Fill test tube A with 3 pipettes full of substance A.
3.Fill test tube B with 3 pipettes full of substance B.
4.Take the Benedict's solution and apply 10 drops of it into each test tube.
5.Swirl to mix.
6.Prepare water bath, take the beaker, fill half with water, and heat to between 40 and 50 degrees C.
7.When water bath is ready, put each test tube into the water bath. Wait 5 minutes.
8.After 5 minutes, remove test tubes from the water bath set in test tube holder and record results. Also turn off hot plate.
9.Clean both test tubes thoroughly.
10. Repeat steps 2 and 3.
11.Add 10 drops of Lugol's solution to each test tube.
12.Swirl to mix.
14.Clean both test tubes thoroughly.
15.Repeat steps 2 and 3.
16.Add 10 drops of Biuret solution to each test tube.
17.Swirl to mix.
18.Wait 1-2 minutes.
3. Data and Results
A. Data Tables
+ or -