How does UCI run O-Chem labs

J. K. Kim

Teaching Guided-Inquiry Organic Chemistry Labs University of California, Irvine

2007

ENROLLMENT STATISTICS

Enrollments (3rd week)

2005 Fall 881

2006 Winter 196

2006 Spring 　

2006 Fall 1065

2007 Winter 247

2007 Spring 　

2007 Fall 1250(projected)

51LA WINTER 2007 SCHEDULE OF EXPERIMENTS

• EXP #1 - Monday, January 8 - Friday, January 12, 2007– Recrystallization of Salicylic Acid and Bromoacetanilide – Read “Techniques..” pp. 100-105 (9.1-9.4), 111 (9.7a), 114 (9.8)-116 (9.9)– Supplementary information in Paula Y. Bruice (4th ed): Chapters 1 & 2.

• EXP #2 - Tuesday, January 16 - Monday, January 22, 2007– Identification of a White Solid. – Supplementary information in Paula Y. Bruice (4rd ed): Chapters 1 & 2.– Read “Techniques..”10, pp. 116-126 and “Modern Projects..” pp. 239-241

• EXP #3 - Tuesday, January 23 - Monday, January 29, 2007– Extraction, Drying Agents, and Sublimation. – Read “Tech..” – Read “Techniques..”, 8.1-8.3 (pp. 75-84), 8.5-8.10 (pp. 85-98), and 12.1-12.2 (pp. 158-16

0)– Supplementary information in Paula Y. Bruice (4rd ed): Chapters 1 & 2.– Exp. 1: Extraction of Caffeine from Tea. – Microscale Procedure, pp. 6-8 in “Modern Projects..”.– Exp. 2. Purification and Thin Layer Chromatographic Analysis of Caffeine. – Microscale Procedure, pp. 9-14 in “Modern Projects..”.– Do the purification by sublimation part only.

• EXP #4 - Tuesday, January 30 - Monday, February 5, 2007– Thin Layer Chromatography. – Read “Tech..” 15.1-15.8 (pp. 177-189)– Thin-Layer Chromatography. Handout Experiment #4.

• EXP #5 –Tuesday, February 6 - Monday, February 12, 2007– Separation of Organic Mixtures– Read “Techniques..” 8, pp. 75-99)– Supplementary information in Paula Y. Bruice (4rd ed), Chapters 1 & 2– Project 2. Using Extraction to Separate a Mixture, pp. 243-246 in “Modern Projects..”– 2.1 Separation and Purification of the Compounds in the Unknown Mixture: First Wee

k. Miniscale Procedure, page 244-245 in “Modern Projects..”– 2.2 Melting Points, purity, and Identification of the Compounds in the Mixture: Second

Week. Miniscale Procedure, page 245-246 in “Modern Projects..” (Extra Credit)

• EXP #6 - Tuesday, February 13 - Wednesday, February 21, 2007– Boiling Points and Distillation

NOTE: Students in Monday sections are scheduled to do the lab work on Wednesday, February 21 instead of Monday, February 19.

– Read “Techniques..” 11.1-11.4, pp. 127-145.– Apparatus Set-up in Fig. 11.6 (page 134) and 11.15 (page 144) in ”Techniques”.– Supplementary information in Paula Y. Bruice (4rd ed), Chapters 1 & 2– 1. Simple Distillation of an Unknown Mixture (Techniques 11.3, pp. 133-136)– 2. Fractional Distillation of an Unknown Mixture (Technique 11.4, pp.142-145)

NOTE: Carry out the distillation in the hood.– 3. Refractometry and Refractive Index (Read “Technique..” 13, pp. 161-164)

• EXP #7 - A Dry-Lab – STEREOCHEMISTRY:AN EXERCISE WITH MOLECULAR MODELS

HANDOUT EXPERIMENT– Answer questions in the exercise packet.Exp #7 and return the packet to your TA.– Supplementary information in Paula Y. Bruice (4th ed), Chapter 5.– Assignment is due by 5 PM Wednesday, February 28, 2007

• EXP #8 - Thursday, February 22 - Wednesday, February 28, 2007– Bromination Reaction of Alkenes: Mechanistic Study

Supplementary information in Paula Y. Bruice (4th ed), Chapter 4.7– Exp. 16.2 Stereochemistry of Bromine Addition to trans-Cinnamic Acid, – pp. 139-142 in “Modern Projects..” Microscale procedure (p 141)

• EXP #9 - Thursday, March 1 - Wednesday, March 7, 2007– Isolation of Essential Oils From Plants. – Read “Techniques..” 11.7, pp. 129-132 & “Techniques..” 14 (Optical Activity and Polari

metry), pp.140-149.– Supplementary information in Paula Y. Bruice (4rd ed), Chapters 5– Exp. 6.2 Isolation of (R)-(+)-Limonene from Orange Peels, – Miniscale Procedure, p 44-46 in “Modern Projects..”– Steam Distillation, Isolation of Limonene, Polarimetry experiment (the measurement of the o

ptical activity and calculation of the specific rotation) will be introduced at the time of experiment. (Read Technique 14)

– Prelab Questions: Answer Questions- 1-4, page 149 in “Techniques..”.– Post-Lab Assignment: Answer Questions- 1, page 46 in “Modern Projects..”

EXPERIMENT #1Recrystallization of Salicylic Acid and Bromoacetanilid

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• Monday, Jan 8 - Friday, Jan 12, 2007• Reading Assignment for Exp #1:

Review Techniques: pp. 100-105 (9.1-9.4), 111 (9.7a), 114 (9.8)-116 (9.9)- Familiarize yourself with the Appendix in Techniques, page A1 -A6.- Read the Safety link. Read the Lab Policies link. - Read the Keep our lab Clean link.

Supplementary information in Paula Y. Bruice (4th ed): Chapters 1 & 2.

Pre-Lab Questions:1. The proper procedure for recrystallization is to allow the hot solution to cool to room t

emperature, then to chill the solution in an ice bath. Why do we not simply chill the hot solution in an ice bath initially?

2. Explain whether or not each of the following pairs of solvents might be useful as a solvent pair for recrystallization. (See “Tech..”, Table 9.1, p. 101 and 9.2, p 104. Read “Choice of Recrystallization Solvent” on pp. 101-102. Table 15.1 on page 187 lists the relative polarities of common organic solvents.(a) ethanol-methanol (b) hexane-cyclohexane (c) acetone-ethanol (d) water-ethanol (e) water-cyclohexane

• Recrystallization is one of the major techniques for purifying solid organic compounds. A pure organic compound is one in which there are no detectable impurities. By finishing Experiment #1, you will master the technique starting with two compounds that are structurally different.

• Safety Information– Salicylic acid may cause skin rashes in sensitive individuals. Ingestion of large

amount can cause vomiting, abdominal pain, increased respiration, acidosis, mental disturbances. Wear gloves, avoid all contact with skin, eyes, and clothing, and do all work in an efficient fume hood.

– Bromoacetanilide is known as analgesic and antipyretic.– Ethanol is flammable and causes nausea, vomiting, flushing, metal excitement,

or depression, drowsiness, impaired perception, coma. Avoid breathing and avoid contact with skin, eyes, and clothing.

EXPERIMENTAL

• A. Recrystallization of Crude Salicylic Acid– From the solubility data in -"Modern Projects and Experiments in Organic Che

mistry (“Modern Projects..”), Table 4.1 Solubility of Salicylic Acid in Water, page 25, calculate the minimum volume of hot water needed to dissolve 100 mg of salicylic acid.

– Rewrite the procedure in “Techniques..”, 9.7a on page 111 to recrystallize 100 mg of crude salicylic acid in the pre-measured water (Steps 3 and 4 will be omitted) Remember that the actual volume of water needed is just a little less than the calculated minimum volume because the solubility of salicylic acid is much higher at the boiling temperature of water. Record the initial and recovered amount (mass), and calculate % recovery. Submit your product to your TA in a properly labeled vial. Melting point determination of the recrystallized salicylic acid will not be performed.

• B. Recrystallization of Crude Bromoacetanilde– By following the procedure in “Techniques..”, 9.7a, write a procedure to recrystal

lize approximately 100 mg of a crude 4-bromoacetanilide containing small amount of 2-bromoacetanilide. Use a solvent pair of ethanol and water. Record the initial and recovered amount (mass), and calculate % recovery. Submit your product to your TA in a properly labeled vial.

• Post-lab Assignment– Answer Questions 1-3 on p. 116 in “Techniques..”

UCI O-Chem Oral Presentations

• Being able to communicate effectively will be an important aspect of any career. Communicating science effectively can be especially challenging, so we’re giving you a chance to practice that skill here in Chem 51LA.

• Your goal for this presentation should be to teach the rest of the class what your group learned from the experiment.

• Here are some guidelines and suggestions to help you as you prepare for your group’s presentation.

• General Information – Don’t panic! Take a few deep breaths. – Remember that when you are giving an oral presentation for an experiment, you do not hav

e to turn in a written discussion, – Be sure to schedule meetings with your group members. Don’t leave preparation for this pr

esentation to the last minute! – Talk with your TA about your presentation. If you don’t understand some aspect of the expe

riment or need some help interpreting a result, ask your TA, but don’t wait until the day before your presentation!

– We are all adults in this class, so let’s remember to behave appropriately. Whether you are giving the presentation or are part of the audience, you should behave in a respectful and supportive manner toward your TA and classmates.

• Time – Presentations will be given at the beginning of the lab period following the period in which you

conducted the experiment (when you would normally turn in a written discussion). – Plan your presentation to be 15-20 minutes. It’s a good idea to practice a few times and time

yourselves. • Format

– The exact format of the presentation will be up to your group. There are, however, some guidelines that need to be followed.

– Each group member must participate in the actual presentation as well as preparation. – Keep it interesting. Monotone lectures for 20 minutes are not effective presentations. Think

about how you would like someone to teach the material to you. – Because these presentations are given in the lab, we are unable to provide projectors or other

technology.– You should, however, use the whiteboard in your presentation. – Engage your audience. Feel free to ask your classmates questions during the course of your

presentation.• Content

– Remember the goal of your presentation is to teach the rest of the class what your group learned from the experiment.

– The content of the presentation should be similar to what you would write in a discussion, but you should not be simply reading a discussion to the class. Check the 51LA Lab Report handout (on the class website) for what should be included in a discussion.

– If members of your group obtained different or conflicting results, be sure to discuss this in your presentation. Think about (and explain in your presentation) why results differed, how discrepancies could be reconciled, and how the results relate to the purpose of the experiment and underlying theories and concepts.

– Remember to answer any post-lab questions during your presentation.• Grading

– Presentations are worth a total of 30 points. – Each member of the group will receive the same Group Score for the actual presentation (20 pts

maximum). – Additionally, you will receive an Individual Score for participation (10 pts )

• Group Score • Explanation and Incorporation of Theory and Principles (5pts)

– 5: Great—Group shows thorough understanding of the goals and underlying principles of the experiment. Group is able to explain these concepts to other students clearly and in their own words. Different members of the group are able to answer most questions from their audience. It is very clear to the audience and TA that the group understands and can explain what they did and why they did it.

– 4: Very Good—Group is able to relay most concepts involved in the experiment, but may need a bit more explanation. Descriptions of concepts and principles are in group members’ own words, not recited from textbooks. Members are generally able to answer questions from the audience. Group has a general grasp of the purpose of the experiment. maximum).

– 3: Good—Group demonstrates understanding of several, but not all of the underlying principles of the experiment. Explanation of concepts are satisfactory, but could be elaborated upon. The group may be able to answer some questions adequately, but struggles with others. Group has satisfactory understanding of the purpose of the experiment.

– 2: O.K.—Group demonstrates a below average understanding of concepts relating to the experiment and struggles to explain these concepts to the audience. Explanations may be regurgitations of textbook definitions. The group has a difficult time answering most or all questions from the audience.

– 1: Poor—Group demonstrates minimal, if any, understanding of concepts relating to the experiment and/or cannot communicate these concepts to the audience. Explanations, if present, are regurgitations of textbook information. Group is unable to answer most questions.

– 0: Absent—No incorporation or explanation of underlying theories and principles.

• Discussion of Results (5pts) – 5: Great—Group discusses results and their meaning in a way that is easily understandable to the

audience. Differing or conflicting results among group members are explained thoroughly. Meaning of results is clearly related to purpose of experiment and underlying concepts.

– 4: Very Good—Group discusses results and their meaning in a way that is generally understandable to the audience. Differing or conflicting results are mentioned and discussed briefly. Group is generally able to relate results to purpose of experiment and underlying principles.

– 3: Good—Group mentions results and provides limited explanation. Discussion of results may not be clear to audience at all times, but it is generally understandable. Differing or conflicting results are at least mentioned, but may not be explained well. Results are tied to purpose and underlying concepts minimally.

– 2: O.K.—Group mentions results but fails to provide a clear explanation of them. Differing or conflicting results are ignored or not explained. Results are related to purpose and underlying concepts superficially if at all.

– 1: Poor—Group leaves out some results or fails to explain them at all. Results are not tied to purpose or underlying principles.

– 0: Absent—No discussion of results.

• Discussion of Error (5 pts) – 5: Great—Group thoroughly analyzes and explains several possible reasons for error and

ties them into underlying principles of experiment. – 4: Very Good—Group thoroughly analyzes and explains some possible reasons for error

and ties them into underlying principles of experiment, but important possible reasons for error were omitted.

– 3: Good—Group analyzes and explains some possible reasons for error, but could elaborate further. Some important explanations may be missing. Explanation of error generally ties into underlying principles of experiment.

– 2: O.K.—Group mentions reasons for error, but fails to provide a clear explanation of them. Explanations are related to underlying concepts superficially if at all.

– 1: Poor—Group leaves out or fails to explain several reasons for error. Explanations are not tied to underlying concepts of experiment.

– 0: Absent—No discussion of results.

• Incorporation of Post-Lab Questions (3 pts) – 3: Good/Great—All post-lab questions are answered completely and correctly. – 2: OK/Good—All post-lab questions are attempted, but some answers are incorrect. – 1: Poor—Some post-lab questions are missing and/or most answers are incorrect. – 0: Absent—Post-lab questions are not addressed.

• Quality of Presentation (2 pts) – 2: Good/Great—Presentation is well organized, flows well between presenters, and

engages audience. – 1: OK/Good—Presentation is somewhat organized, has ok flow between presenters, may

not keep audience engaged. – 0: Poor—Organization and flow are clearly lacking in presentation.

• Individual Score

• You will be rated by your group members on a scale of 1-5 (5=highest) in each of the following categories:

1. Attendance at meetings 2. Meeting preparedness 3. Willingness to participate 4. Positive attitude toward group members 5. Overall contribution

• Scale for categories 1-4: – (5) His/her performance in this category was great. It highly exceeded my expectations. – (4) His/her performance in this category was good. It slightly exceeded my expectations. – (3) This person met my expectations in this category. – (2) His/her performance in this category was poor. It was slightly below my expectations. – (1) His/her performance in this category was very poor. It was way below my expectations.

• Scale for category 5: – (5) Overall, this person was a great partner. He/she was always prepared and shared their strengths with the

group. He/she highly exceeded my expectations for a group member. – (4) Overall, this person was a really good partner. He/she slightly exceeded my expectations. – (3) Overall, this person was a good partner. He/she did not do more than was necessary, but they pulled their

own weight. He/she met my expectations for a group member. – (2) Overall, this person was ok. He/she put in more than minimal effort, but I don’t feel they did as much as they

should have. He/she did not meet my expectations for a group member – (1) Overall, this person could not be counted on. He/she put in minimal effort.

Average of all raters and ratings

> 18 15-17 13-14 11-12 9-10 7-8 5-6

Total individual points 10 9 8 7 6 5 4

Chem 51LA Lab Reports

Lab reports for Chem 51LA should be written in you lab notebook in ink and consist of the following sections:

TO BE COMPLETED BEFORE YOUR LAB SECTION

1. Title: The title for an experiment should be short but descriptive so that you can easily recognize which experiment it is.

2. Date and Lab Partners: The actual date that an experiment was performed as well as the names of other students with whom you were working should be recorded. If you don’t know who you are working with in advance, you should add your lab partners’ names at the beginning of the experiment.

3. Purpose: Every experiment has a purpose! This section should be a brief (but more than one sentence) description of the reason that the experiment is being performed and what methods or techniques will be used. “Because it’s on the lab schedule” is NOT an appropriate purpose for an experiment. Instead, think about what the goals of the experiment are. Will you be separating the components of a mixture of compounds? By what method will you achieve separation? Are you discovering the identity of an unknown compound? What techniques can be used to identify the compound? If there are multiple parts to an experiment, they should all be included here. The clarity of this section will indicate to your TA how well you understand what you will be doing and why you will be doing it.

4. Reactions: If the experiment includes synthesis, the pertinent balanced chemical equation (using structures) should be written here. This section may be omitted when synthesis is not part of the experiment.

5. Table of Chemicals (Including Physical Data): A table of all chemicals used in the experiment along with their physical properties (molecular mass, melting point, boiling point, and density) should appear here. This table should also include the moles (or millimoles) and quantities (mass or volume) of each chemical to be used in the experiment. These calculations must be performed as part of your pre-lab preparation.

6. Procedure: Outline the procedure for the experiment here, including any changes indicate in the handout for the experiment. This section should be written IN YOUR OWN WORDS and in a format that you can easily follow when necessary in the laboratory. You should NOT copy the procedure word for word from the text book or experiment handout! Diagrams or drawings of equipment should be included in this section as well.

TO BE COMPLETED DURING YOUR LAB SECTION

7. Data and Observations: In this section you should record any data collected during the experiment as well as the ACTUAL amounts of chemicals used. Note any observations you make during the course of an experiment such as a color change, the presence or disappearance of a solid, and any difficulties experienced. Be detailed when recording observations. When an experiment fails, you may need to rely on these observations to determine what happened.

8. Results: Briefly summarize the results of your experiment here. Include calculations of percent yield or percent recovery.

TO BE COMPLETED AFTER YOUR LAB SECTION

9. Discussion: This is your chance to write like a scientist. Your discussion should begin with an overview and a brief description of the goals of the experiment. Explain what happened and why, relating your discussion of results to the goals of the experiment. Use your data to support any conclusions drawn. Consider the following questions, if appropriate, when writing your discussion.

a. Do your results make sense? b. Were the goals of the experiment accomplished? c. How do your results compare to literature values (melting point, boiling point, spectroscopic d

ata, etc.)? d. How do your results relate to the underlying theories of the experiment? e. What are the possible sources of experimental error? How do they relate to your results and

the underlying theories of the experiment? f. What difficulties, if any, were encountered during the course of the experiment, and how did t

hey affect your results? Do these difficulties suggest a better way to conduct the experiment?

g. Do your results raise questions that could be answered by further experiments? What would those experiments be?

h. If you have synthesized a compound, how do you know its identity? i. If you have isolated a compound, how do you know how pure it is? What is your percent reco

very or percent yield? j. If your percent recovery or percent yield is low, why may that be? Did you lose material alon

g the way? Are you sure you actually made what you think you made, or did you recover reactants? Discussions should be written in the third person passive voice. For example, “We dissolved the white solid in 10 mL of hot water,” should be written as, “The white solid was dissolved in 10 mL of hot water.”

**Oral Discussions: When you are required to present an oral presentation for an experiment, the same questions should be considered as in the written discussion. You are not, however, required to use the third person passive voice. While the group oral discussions should relay the same information as the written discussion, they should not be recitations of written discussions. The oral presentation should keep the attention of and engage your audience. Being able to relay scientific information effectively is a very important skill for any job that you should begin practicing now.

Turning In Lab Reports Your TA will check your notebook during your lab section for all portions of the report except for the discussion. The only portion of the report that needs to be handed in is the discussion during the next lab period or other specified time.