Moore, Timothy
Moore, Timothy
Instructor: Mrs. Tammy Moore
Class: VHSG Online Chemistry
26 October 2009
EXPERIMENT 5.1
Measuring the Width of a Molecule
This lab allows the width of a molecule to be computed from experimental data.
Abstract
[What you will put here: Summarize the whole report in one, concise paragraph of about 100-200
words. You cannot write the abstract until after you've completed the report. Because it assumes that
you will speak to your conclusion or what you learned in brief.]
Introduction
[What you will put here: In this introduction, some background is provided for the reader
(sources are noted in the reference section at the end of the report).Typically, the introduction states the
problem to be solved or the experiment to be performed and explains its purpose and significance. It
also provides whatever background theory, previous research, or formulas the reader needs to
understand to perform the experiment (or solve the problem).]
Methods and Observations
Materials
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Water
Eyedropper
Spoon (to stir)
Large glass
Graduated cylinder
Dishwashing liquid
Large bowl
Pepper
Ruler
Safety goggles
Moore, Timothy
HEATING PHASE:
Procedure:
1. I filled large bowl almost full of water, leaving only a centimeter or so from the top of the
water to the rim of the bowl. I put the bowl where it wouldn’t be disturbed.
2. I measured out 5 mL (1 teaspoon) of dishwashing liquid into the graduated cylinder.
3. Leaving the dishwashing liquid in the graduated cylinder, I filled the cylinder up to the
50 mL (1/4 cup) mark with water. I did it slowly to reduce the formation of bubbles.
4. I poured the contents of the cylinder into the large glass.
5. I filled up the empty cylinder to the 50 mL mark with water and poured it into the same
glass.
6. I repeated this step six more times to that a total of 395 mL (2 cups) of dishwashing
liquid was in their tall glass.
7. I stirred the contents slowly but thoroughly. This made the 5 mL of dishwashing liquid
diluted to 400 mL.
8. Next, I calibrated my eyedropper. I cleaned and dried the graduated cylinder.
9. I used my eyedropper to transfer 10 mL of the diluted dishwashing liquid (drop by drop)
into the cylinder. I counted how many drops it took to fill the cylinder up to the 10mL
mark.
10. I took the number 10 and divided it by the number of drops that I counted. I took the
pepper over to the bowl of water (the water was calm since it had not been disturbed).
11. I lightly sprinkled the pepper onto the surface of the water in the bowl evenly so there
was pepper on each part of the water’s surface but not too much.
12. I used the eyedropper to put one single drop of diluted dishwashing liquid in the very
center of the bowl. I observed what happened.
13. I used my ruler to measure the diameter of the circle.
14. I used the mole concept and size of the circle to determine the molecules.
15. I took the volume of one drop that I calculated when I calibrated the eyedropper. I
multiplied that volume by the density of the diluted dishwashing liquid, which was 1
gram/mL. That gave me the number of grams of solution I dropped into the water.
16. Only 0.0125% of the solution was sodium stearate, so I took the number of grams I just
calculated and multiplied it by .000125. This told me how many grams of sodium
stearate I added to the bowl.
17. Using the chemical formula for sodium stearate (NaC18H25O2) I calculated the
molecular mass of sodium stearate.
18. I used the molecular mass of sodium stearate to convert the grams of sodium stearate
into the circle, and took the number of moles I just calculated and multiplied it by 6.02 x
10 23 (Each mole contains 6.02 x 10 23 molecules).
19. Next, I found the area of the circle (using Area=3.14r2).
20. I took the area and divided it by the number of molecules that I had calculated. The
results gave me the area occupied by each individual molecule.
21. I estimated the molecule’s width by assuming that the molecules are roughly squares.
I took the square root of the area calculated and had a good estimate.
22. I cleaned up my mess.
Moore, Timothy
Observation/Data
[enter your observations, data, and calculations here.]
Conclusion
My observations [You must explain, analyze, and interpret your results, being especially careful
to explain any errors or problems. This is probably the single most important part of the report, since it
is here that you demonstrate that you understand and can interpret what you have done. Read Dr. Wile’s
explanation of the experiment in the text. Just don’t copy it word for word. ]
References
[Use MLA citation standards. This is commonly used in lab reports, but APA is used in some colleges
too. I encourage you to do some of your own research too and add to the introduction section of the lab
report from what you learn.