Question:

I need help filling in tables and answering questions to this lab.  I am absent of lab equipment and need this done! Thanks.

Experiment 1: Modeling Basic Organic Compounds

In this experiment you will make molecular models of various hydrocarbons and then test unknowns for the presence of either carbohydrates or lipids.

Materials:54 Raisins 24 Marshmallows

80 Toothpicks

Procedure

1. For each of the structures listed in Table 3, draw the structure named, count the number of carbon atoms and hydrogen atoms, count the number of C-H bonds, count the number of C-C, and count the number of bonds.
2. Construct models of each of the organic compounds using the raisins (hydrogen atoms), marshmallows (carbon atoms), and the toothpicks (each represents a single bond) in your lab kit. Refer to Table 3 for specific molecules to construct. The first example, propane, is drawn below.

Table 3: Carbon Molecule Data
Compound	# H Atoms	# C Atoms	# C-H Single Bonds	# C-C Single Bonds	# Double Bonds	# C≡C Triple Bonds	Chemical Formula	Structural Formula
Propane	8	3	8	2	0		C3H8	CH3CH2CH3
Butane
Heptane
Ethene
Butyne
Hexene
Methane

Post-Lab Questions:

Which organic compounds contained double bonds? Triple bonds?

Draw an organic molecule that was not included in Table 3 that contains a double bond. Name the compound.

Experiment 2: Testing for Carbohydrates

In the following experiment, you will test for the presence of different organic compounds. You will use water as a negative control. A negative control will result in no change in color. For example, if you are testing for the presence of carbohydrates, the test chemical, IKI solution, will remain the original color when mixed with water.

Materials:1 pinch of Unknown A 10 Drops of Unknown B 10 Drops of Unknown C 1 pinch of Unknown D 3 – 4 drops IKI Solution 5 Test tubes Test tube rack

3 Pipettes Permanent marker 10 mL Graduated cylinder *Distilled Water*You must provide

Procedure

1. Place five test tubes in the test tube rack.
2. Use a permanent marker to label each test tube as Unknown A, B, C, and D. Label the fifth test tube “water”.
3. Place one pinch of powdered Unknowns A and D into their respectively labeled tubes. Then, add 10 mL of water into test tubes A and D.
4. Use a pipette to place about 10 drops of unknowns B and C into their respectively labeled tubes.
5. Place 10 drops of water in the “water” test tube.
6. Add three to four drops IKI solution to each test tube and observe any color change. If a carbohydrate (starch) is present in the unknown, the solution will turn a purple-black color upon addition of the IKI solution.
7. Record your observations in Table 4. A positive result (visible color change) indicates that starch was present. A negative result (no color change) indicates that there was no starch.

Table 4: Starch Presence Results
Unknown A	Unknown B	Unknown C	Unknown D	Water

Post-Lab Questions:

1. Which unknown(s) contained a carbohydrate? How do you know?

Experiment 3: Testing for Lipids

Materials:1 pinch of Unknown A 10 Drops of Unknown B 10 Drops of Unknown C 1 pinch of Unknown D Newsprint paper (2) 50 mL Beakers 10 mL Graduated cylinder

5 Pipettes Permanent marker Stir rod *Water*You must provide

Procedure

1. Label five small sections of your newsprint paper with letters A- D and the last section “water”.
2. Measure 10 mL of water in the graduated cylinder.
3. Add one pinch of Unknown A to the graduated cylinder. Stir with the stir rod to create a homogenous solution, and transfer the solution to a 50 mL beaker. Label this beaker “Unknown A”.
4. Rinse out the graduated cylinder, and measure 10 mL of water in it.
5. Add one pinch of Unknown D to the graduated cylinder. Stir with a stir rod to create a homogenous solution, and transfer the solution to a 50 mL beaker. Label this beaker “Unknown D”.
6. Rinse out the graduated cylinder, and measure 10 mL of water into it.
7. Use clean pipettes to pipette one drop of Unknown A, Unknown B, Unknown C, and Unknown D onto each of the corresponding newsprint sections.
8. Pipette one drop of water (from the 10 mL graduated cylinder) onto the final section labeled “water”.
9. Observe and compare the translucence of each unknown. Compounds containing lipids will have a higher translucence than water (i.e., the words under the drop on the newsprint will be harder to read with a lipid containing sample).
10. Record the information, in order of translucence (0, +, ++, +++, ++++) in Table 5. The unknown which contains the most lipids should be recorded as ++++.

Table 5: Lipid Test Results
Unknown A	Unknown B	Unknown C	Unknown D	Water

Post-Lab Questions:

1. Which unknown(s) contained a lipid?
2.  Draw the chemical structure of a carbohydrate and a lipid of your choice. Name the structures you draw.
3. Why was water used as a negative control in the experiments in this lab?

 

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