Organic Compounds Lab

Name Period Date

I. Topic: Compounds found in foods.

II. Problem: Carbohydrates, proteins, fats, vitamins, and other nutrients provide your body with energy necessary to carry on life activities. These compounds are present in the plants and animals you use as food. In this lab, you will test for specific organic and in organic compounds and then determine if those compounds are present in ordinary foods. (You will test for specific compounds present in food by using chemicals called indicators).

III. Hypothesis: Write a hypothesis that predicts what compounds you think you will find in the mystery meal.

IV. Theory: Discuss the following questions with your lab group before you start the lab. 1. What is an indicator? 2. What is Benedict’s solution used to test for? 3. What is Biuret solution used to test for? 4. What is Iodine (Lugol’s) solution used to test for?

V. Materials:  beaker  markers  1% silver nitrate solution  graduated cylinder  hot plate  Blender  test tubes  Benedict's solution  refrigerator  test tube clamp  Biuret solution  ”meal” to test  masking tape  Lugol's iodine solution   VI. Procedure:  PART 1: McMUSH  1. Each group will be given a “meal” to test and analyze. Place the “meal” in a blender. Add enough water to cover and blend until you get an emulsion (liquid mixture). (This may have been done for you already.)  2. Filter the mush in to a beaker. (This may have been done for you).  3. In the data table provided, predict the substances you will find in the “meal” solution.  4. Record your predictions in the data table by writing a “+” or “-“under the “Predictions” column.  5. Repeat the indicator tests from this week using 5 ml of the McMush solution.  6. Describe and record your results.   PART 2: McMUSH-DEMONSTRATION OF FAT CONTENT  1. The complete meal will be blended to make the McMush.  2. A large sample of the meal will be heated.  3. From the heated sample, 100 ml will be taken to be cooled.  4. Results from the 100 ml sample are representational of the complete meal.   Procedure: 1.Preheat the hot plate. 2.Break up meal into small pieces and blend. (This may have been done for you already.) 3.Pour part of the blended McMush into a 500 ml beaker. 4.Add 100 ml of water to the McMush and stir well. 5.Boil McMush mixture gently for 15 minutes. 6.Use oven mitts to protect your hands and pour the hot McMush mixture into a graduated cylinder. Then cool in the refrigerator for 5 minutes. 7.Remove McMush from the refrigerator and measure the amount of accumulated fat at the top of the graduated cylinder. 8.Record results. 9.Clean glassware with warm soapy water.    Expected Outcome:  The fat will form a layer at the top and solidify as it cools. You may calculate the percent of fat in the McMush meal by dividing the ml of fat by the total ml of your sample. For example, you might find 40 ml of fat out of a total of 100 ml of sample. This would indicate that the total meal contained 40% fat.   VII. Results:  Record your results in a data table that you have copied onto a clean sheet of paper:    EXPEC  PREDIC  ACTUA INDICATO TED TION L R TEST RESUL RESULT TS S  Biuret    solution  Benedict’s    solution  Lugol’s    iodine solution  Refrigerator   %  test %   DESCRIPTION OF “MEAL”:    VIII.: Analysis  1. What was the function of each testing reagent that you used? Be specific in identifying each reagent and explaining what it tests for.  2. Why did we test known substances before testing the unknown substance (the McMush)? Provide an example of a known substance that you tested, and what you were looking for in the unknown substance.  3. How did the results of all the known substances compare with the unknown substance?  4. You have tested the organic and inorganic composition of a Happy Meal. Are there any results that worry you in terms of its nutritional value? Please include references to the main classes of organic molecules in your answer, and support your explanation with specific examples from your data tables.  5. People with diabetes are instructed to avoid foods that are rich in carbohydrates. How could your observations in this investigation help you decide whether a food should be served to a person with diabetes?   IX. Discussion & Conclusion: (Discuss what happened in the lab. Give details on anything that went wrong. Don’t just tell what went wrong, explain why it went wrong. What did you learn? What conclusions can you draw from the results of this lab assignment? Compare the results of the experiment with your hypothesis, if necessary. How does the experiment relate to everyday life?) 