I need help with an assignment it is a doc file about a chemistry lab I really need help with the charts. Thank You
Biology Fall 2014 Organic Chemistry Pre-Lab
Name:
Date:
Class:
What is the purpose of this lab? |
Hypothesis: Generate your predictions hypothesis based on the introduction that you have read in this lab and check off which organic compound is found in each of your samples.
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Tests: Chemicals are used many times as indicators, that they show us if the presence of specific biomolecules can be found in given substances. This lab focuses on identifying biomolecules using indicators. Read the procedures and complete the indicator table below.
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Organic Compound Lab
Introduction
A characteristic of life is molecules containing carbon. These are called organic molecules. In our class we have been referring to them as organic compounds or biomolecules since they are necessary for life. The most common organic compounds found in living organisms are lipids, carbohydrates, proteins, and nucleic acids. Common foods, which often consist of plant materials or substances derived from animals, are combinations of these organic compounds. Simple chemical tests with substances called indicators can be conducted to determine the presence of organic compounds. A color change of an indicator is usually a positive test for the presence of an organic compound.
Purpose
To use indicators to test for the presence of lipids, carbohydrates, and proteins in various foods.
Materials
Indicators (Biuret reagent, Benedict’s solution, Iodine solution)
Foods in beakers, test tubes, test tube holder, hot plate, large beaker, brown paper, well plates
Procedures: see next page
Data Table
Substance | Lipid Test | Carbohydrate Tests | Protein Test | ||||||||
Spot or No Spot | Lipids Present? | Sugar Test | Starch Test | Biuret Color | Proteins Present? | ||||||
Benedict Color | Sugar Present? | Iodine Color | Starch Present? | ||||||||
Milk | |||||||||||
Apple Juice | |||||||||||
Oil | |||||||||||
Flour | |||||||||||
Water | |||||||||||
Which test substances contain lipids?
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Which test substances contain starch?
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Which test substances contain sugar?
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Which test substances contain protein?
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Which substances did not test positive for any organic compound?
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Biomolecule Lab Procedures
Part I - Testing for Lipids
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Part II - Testing for Carbohydrates Starches and simple sugars (saccharides) are two common types of carbohydrates. Sugar (saccharide) Test
When heated, Benedict’s solution will change color from blue to yellow, orange, or red in the presence of a sugar.
Starch Test
Iodine Solution will change from brown to blue/black in the presence of starch.
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Part III – Testing for Proteins
Biuret reagent changes to blue-violet in the presence of protein.
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Biomolecules Lab Conclusion
Write-Up Guidelines
First Paragraph: Answer the following question to prepare for your write-up. Turn this information into your introductory paragraph.
Which organic compound (s) did you test for in this lab?
What were the test chemicals (reagents) you used to do the tests?
What food substances did you test?
Body Paragraphs: Write one paragraph for EACH test you did in this lab. Make sure you cover the information in the question below. Be sure to use complete sentences.
What is the name of the test substance and what does it test for?
Describe the organic compound you are testing for.
How do you know from the test that this organic compound is present?
What were the results of the test?
What can you conclude from the results about the presence or absence of this organic compound in each substance?
EXAMPLE:
Here is a good example of how to write one of your paragraphs. It is taken from a lab activity on acids.
Litmus paper can be used to test for the presence of acid. Acids are substances that contain hydrogen ions. They are sour in taste. Strong acids can burn you. Litmus paper turns pink the presence of an acid. When we tested the lemon juice the paper turned light pink; the vinegar turned the paper a darker pink; the buffer solution and the distilled water didn’t change the paper at all. From these results I concluded that lemon juice and vinegar are acids and that the buffer solution and distilled water are not.
Conclusion: Write a paragraph summarizing all of the positive results. Describe anything that might have affected your results. Make a suggestion for improving the lab in the future.