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CH342-02, Organic Chemistry Lab 1, Fall 2009
Tuesday, Second Eight Weeks
Instructor: / Dr. Bruce HathawayOffice: / Rhodes 201E
Phone: / 651-2370
Office Hours: / MTWF 9-9:50 AM; or by appointment
Course Web Page: /
e-mail: /
Pre- or corequisites: CH-341, or consent of instructor.
If you drop CH-341, you must drop this course as well!
Assignments / Value / Grading ScaleLab Reports & Products: / 75% / A: 90-100%
Pre-lab Write-ups: / 10% / B: 80-88.9%
Comprehensive Written Final Exam: / 15% / C: 70-77.9%
D: 60-66.9%
F: 0-59.9%
Required Materials:
Lab Text: “Multiscale Operational Organic Chemistry”, by John W. Lehman.
Safety Goggles: May be obtained at the Chemical Storeroom.
Bound Notebook: May be purchased at University Bookstore, Wal-Mart, K-Mart, etc.
General Course Procedures:
In the lab, we try to emphasize techniques that practicing organic chemists use, and give you the experience of actually performing some of the chemistry you learn about in lecture. For you to get the most out of lab, you need to be prepared before you come into the lab. Therefore, I will have you look up certain information before you come to lab. This information will be checked, and will be part of your lab grade. This will also help you to work safely in the lab, since you will know what you are working with.
You are required to work during your assigned laboratory period: this is not an “open lab” like some courses. If you come to lab prepared, you will be able to finish during the time allotted. If you have to miss your lab for some reason, please contact me in advance, if possible, and we will work out a time to make it up. Medical reasons will require some verification.
Lab Reports:
Lab reports make up a large percentage of your grade. Since we are only doing seven experiments during the semester, each report is a significant percentage of your grade. Therefore, you need to take care when you write up your reports, so you can earn the most credit.
Each lab experiment has its own report format. In general, they have a title page, a data and calculations section, and questions to answer. If I don’t ask for something in the report format, then you don’t need to include it. For example, I rarely ask for the experimental procedure, since you are doing the procedure in the lab book or from a handout, so you don’t need to include it in the report. If I do ask for something, and you don’t include it, you will miss points. I am somewhat picky about things. For example, I ask for a descriptive title with a word limit, such as between 15 and 25 words. I count the words, so if you give me a 10 word title, you will lose points. Also, I’m looking for a descriptive title, not just the one in the lab book, so if you copy that title, you will lose points as well.
The questions in the report are thought questions. For example, I want to find out if you understand why something happened, or how you figured out what unknown you had. One sentence copied from the lab book is not sufficient. If I ask “Why?” explain it to me in detail. I am not looking for pages of words, but clear and complete explanations.
Lab reports must be word-processed, except for chemical equations or calculations, which must be written in ink. Turn in your lab reports in the appropriate drawer by Magill 211.
Plagiarism:
Plagiarism is the act of passing someone else’s work off as your own. It is also using the essential style and manner of expression of a source as if it were one’s own. Why do I bring this up? When you work in pairs, you will have the same data as your partner, so your data section will look very similar. When answering the questions, use your own words and thoughts. If I see that two or more people have essentially the same answers to questions written in the same way, I will call that plagiarism, and give each person a grade of ZERO on those questions. This also applies to reaction mechanisms: you can write the same correct mechanism different ways.
Products:
In many experiments, we are making or isolating a product. These products are part of your grade, so keep them. I generally assign 10-20 percent of the lab grade from the products, they are important. You will be turning products in using screw-capped vials. These vials must be labeled in ink neatly, clearly and completely so I know what is in them. Vials are generally labeled as follows:
Your name(s) (not initials)
Name of product, or chemical structure (no abbreviations)
Mass of product
If you do not label your products like this, you will lose points as well. Why am I so picky? First, I need to know what it is and whose it is, so I can grade it properly. When I get a label that says, “AK, recrystallized unknown”, it is hard to know what is in the vial, and whose it is, unless I also have all of your initials memorized. Some semesters, more than one person has the same initials, so this is a problem. Second, I need to dispose of these products correctly, and I need to know what’s in the vial. If it’s not clearly stated, then I have to do a lot more work to figure out how to dispose of the product.
All Experiments will be done on the “Standard Scale”.
Dates / Experiment, (Experiment #, page #) / Reading Assignment / Report Due Date*Oct. 20 / Introduction to Lab, Lab Safety, Calculation of Theoretical Yields, Check-In, Introduction to Melting Point Apparatus (Handout) / Oct. 26
Oct. 27 / Separating the Components of “Panacetin” (2, p. 28-34). Recrystallization and Melting Point Measurement: Identifying the Components of “Panacetin” (3, p. 35-39). / OP12, p. 597
OP15, p. 605
OP25, p. 661
OP30, p. 717
Nov. 3 / Identification of a Component of Panacetin by TLC (Handout).Take Melting Points of Panacetin Solids. / OP19, p. 637
OP30, p.714 / Nov. 9
Nov. 10 / Simple and Fractional Distillation (6, p. 58-64). You will not collect fractions in vials. Instead, collect the distillate in a graduated cylinder, measuring the temperature every 2 mLs. / OP19, p. 637
OP25c, p.675
OP27, p. 679
OP29, p. 703 / Nov. 16
Nov. 17 / Dehydration of Methylcyclohexanols (21, p. 162-171) / OP10, p. 592
OP21, p. 648
OP22, p. 650
OP27, p. 679
OP34, p. 732 / Nov. 23
Nov. 24 / Reduction of Nitro Compounds with Copper (II) Acetate and Sodium Borohydride (Handout) / Nov. 30
Dec. 1 / Properties of Common Functional Groups (14A & B, p. 115-122) & Who Else Has My Compound? (Minilab 14, p.473-4) / OP5, p. 570
OP27, p. 679
OP31, p. 720 / Dec. 7
Dec. 8 / Final Exam, Clean Up and Check Out
*Lab reports are due by NOON on the date indicated. Late lab reports, if accepted, will be penalized severely.
If you do not check out of lab, you will be charged $20, plus the cost of any missing or broken items, if we have to check you out!
The Laboratory Notebook
Your laboratory notebook is THE place where you record ALL information about the experiments you perform. It is meant to be a permanent record; therefore, all entries are to be in INK. If you make a mistake, just draw a line through it - you may discover later that it was correct, and need to see it.
Pre-laboratory Preparation
Before you come to lab, you MUST have certain information in your laboratory notebook. This way, I know you have read the lab, and are ready to work. Having this information in your lab notebook before you come to lab also earns you points toward your lab grade. You can find the information you need in the CRC Handbook of Chemistry and Physics and/or in the Merck Index, or other on-line sources .
Start each new experiment on a new page.
Each experiment must have:
1.A Title
2.A Main Reaction, in those experiments where you are preparing a compound from other compounds.
3.Table of Chemical Data - for starting materials, products, and solvents.
a. Name
b. Molecular weight (Formula weight)
c. Boiling point or melting point
d. Density (for liquids)
e. Solubility in water and other solvents
f. Toxicity
4.Calculation of Theoretical Yield, in those experiments where you are preparing a compound from other compounds.
5.The procedure briefly written out, with room left for observations. This is most easily done by writing the procedure in one column, and leaving another column for observations next to it. You don’t need to copy the procedure word-for-word, but can abbreviate it as you see fit, as long as it is complete.
An Example Calculation of Theoretical and Percent Yields
Assume you started with 4.000 g of CBA (MW = 140.6) and 2.000 mL of cycloheptanone (density = 0.9500, MW = 112.2), and you isolated 3.000 grams of product (MW = 357.3) from the reaction. Notice: All of these numbers have four significant figures, so all of my answers will as well. I count off for wrong numbers of significant figures.
- Calculate the number of moles of the reactants, CBA and cyclohexanone.
CBA: 4.000g ÷ 140.6 g/mole = 0.02845 moles
Cycloheptanone: 2.000 mL × 0.9500 g/mL = 1.900 g. 1.900 g ÷ 112.2 g/mole = 0.01693 moles
- Determine the limiting reagent
The ratio of CBA to cyclohexanone in the balanced equation is 2:1. Therefore, to completely react with the 0.01693 moles of cyclohexanone, there would have to be 2 × 0.01693 moles of CBA, or 0.03386 moles of CBA. We don’t have that many moles of CBA, so CBA is the limiting reagent.
- Calculate the theoretical yield of the product.
0.02845 moles CBA × 1 mole product/2 moles CBA × 357.3 g/mole product =
5.083 g product
- Calculate your percent yield.Assume you isolated 3.000 grams of product.
Percent Yield = (actual yield/theoretical yield) × 100%
(3.000 g/5.083g) × 100% = 59.02%
Diagram of Magill 218