GenChem/Organic Chemistry Laboratory

GenChem/Organic Chemistry Laboratory
Department Office Room 303 Planetary Hall MSN 3E2 Phone FAX Dr. James C. Schornick Office Room 355 Planetary Hall Mailbox Room 303 Planetary Hall Phone Classes (Fall 2014) M – Chem 318 Organic Lab II Sec 201 8:30 pm – 12:20 pm Rm 409 Planetary Hall T – Chem 315 Organic Lab I Sec 204 8:30 pm – 12:20 pm Rm 407 Planetary Hall T – Chem 211 GenChem Lec Sec 004 4:30 pm – 7:10 pm Rm 290 Bull Run Hall (PWC) Office Hours W, R, F 9:00 am – 11:00 am Rm 355 Planetary Hall Course Texts Slayden, Stalick, Roth: Organic Chemistry Laboratory Manual Pavia D., Lampman G., Kriz G., Engel, R., Introduction to Organic Laboratory Techniques, A Small Scale Approach, 2nd ed., Silberberg, Chemistry, Molecular Nature of Matter and Change Web Sites Slayden Schornick Chem Dept

Chemistry 315 - Organic I Laboratory
Syllabus – Fall 2013 Week of Experiment Slayden & Stalick, 2010; Pavia, et al (2nd Ed), 2010 Aug Introduction, Safety, Check-in Slayden pp. 1-20; Pavia pp Sept 3-9 (T –M) Physical Properties Melting Point, Refractive Index Slayden pp Pavia Tech: 1, 2, 3.9; 24, 9 ( , ) Sept 10-16 (T – M) Recrystallization Vacuum Filtration Slayden pp Pavia Tech: 6 (6.2, 6.5, 6.6, 6.9) , 11 ( A, C, D, , 11.6, ) Sept 17-23 Lecture IR, MS, UV Spectroscopy Problem Set Slayden pp Solomons , , 13.9 Pavia Tech: 25 ( ); 28 Schornick: classweb.gmu.edu/jschorni/chem315lab Sept 24 – Sept 30 (T – M) Simple Distillation, Solubility, Density, Ref Index IR Spectroscopy Unknown Pavia Tech: 3 ( ); 13.1; 14 ( ) 25 (25.1, 25.2, 25.4, 25.7) Oct 1-7 Extraction of Caffeine Slayden pp Pavia: pp Oct 8-15 (T – T) Gas Chromatography: Acetates Slayden pp Pavia Tech: 22 ( , 22.9, 22,10, 22.12) Oct (W – T) Distillation of a Mixture: Simple / Fractional Distillation Slayden pp Pavia Tech: Oct 23-29 (W – T) Gas Chromatography: Distillates Slayden pp Pavia Tech: 22 (22.8, 22.11, 22.13, 22.14) Oct 30 – Nov 5 (W – T) Synthesis: t-Butyl Chloride Slayden pp Pavia Tech: 12 ( , ) Pavia Exp: 21 (pp ) Nov 6 – 12 (W – T) Synthesis of Cyclohexene Solomans & Frye pp Pavia: pp Slayden: pp Nov (W – T) Qualitative Organic Analysis: Alkanes, Alkenes, Alkynes, Aromatics, Halides, Alcohols Slayden pp Pavia Exp: 55 (pp , , ) Nov 20– 26 (M – F) Qualitative Organic (con’t) Dec 2 – 6 (M – F) Final Exam; Check out

Chemistry 315 - Organic I Laboratory
Syllabus - Spring 2014 Date Experiment Slayden & Stalick, 2005; Pavia, et al (2nd Ed), 2005 Jan 22, 27 Introduction, Safety, Check-in Slayden pp. 1-20; Pavia pp Tech 1, 2 & 3 Jan 29, Feb 3 Physical Properties Melting Point Refractive Index Slayden: pp Pavia Tech: 9 ( , ); 24 Feb 5, 10 Recrystallization Vacuum Filtration Slayden: pp Pavia Tech: (6.2, 6.5, ); ( ,A,C,D, 11.5, 11.6, ) Feb 12, 17 Lecture - IR, MS, UV Spectroscopy Spectroscopy Unknown Simple Distillation Slayden: pp Pavia Tech: ( ); 28 Solomaon’s: (Sec , ; 13.9) Website: Feb 19,24 Simple Distillation (Boiling Point) Pavia: Tech ; 13.1; ; 25.1, 25.2, 25.4, 25.7 Feb 26. Mar 3 Isolation of Caffeine from Vivarin Tablets Pavia: Exp: pp Mar 5, 10 Gas Chromatography: Acetates Slayden: pp Pavia Tech , , 22.12 Mar 11-17 Spring Break No Lab Mar 19, 24 Simple and fractional Distillation Slayden: pp Pavia Tech pp Mar 26, 31 Gas Chromatography: Distillates Slayden: pp Pavia: Tech 22.8, 22.11, 22.13, 22.14 Apr 2, 7 Synthesis: t-Butyl Chloride Slayden: pp Pavia: Tech , Apr 9, 14 Synthesis of Cyclohexene Slayden: Pavia: pp Apr 16, 21 Qualitative Organic Analysis: (Hydrocarbons, Halides, Alcohols) Slayden: pp Pavia: pp , , Apr 23, 28 Qual Organic (con’t) Apr 30, May 5 Lab Check-out and Final Exam

Chemistry 318 - Organic II Laboratory
Syllabus – Spring 2014 Date Experiment Slayden & Stalick, 2005; Pavia, et al (2nd Ed), 2005 Jan 27 Check-in, NMR Video Feb 3 Lecture: 1. Review - IR, UV, Mass Spec 2. Nuclear Magnetic Resonance Spectroscopy (NMR) Slayden - p Solomons - pp , , , Pavia - p. Techniques 26, 27 ; pp Schornick - Feb 10 Bromination of Toluene (Ortho, Para Substitution) Slayden - p. 61 – 65 Feb 17 Nitration of Methyl Benzoate Meta Substitution Slayden - p. 67 – 69 Pavia - pp , 671, 643 Feb 24 Friedel-Crafts synthesis of 4,4’-de-tert-Butylbiphenyl Slayden - p Mar 3 NMR – NMR Spectroscopy Identification of Unknown Slayden - p. 59 – 60 Pavia - p – 964 Mar 12 Spring Break - No Lab Mar 17 NMR Unknown (cont’d) NMR instructions (Honeychuck) Mar 24 Synthesis of Grignard Reagent Pavia - p. 278 – 288 Mar 31 Synthesis of Benzoic Acid (Continuation of Grignard Exp) Pavia - p April 7 Qualitative Organic Analyses (Aldehydes & Ketones) Slayden - p. 73 – 76 Pavia - p. 470 – 474 April 14 Synthesis of Isopentyl Acetate (Banana Oil) Pavia - pp , , Schornick - Apr 21 Synthesis of Dibenalacetone Slayden - p Apr 28 Synthesis of biodiesel from vegetable oil Slayden - p. 77 Pavia - p. 207 – 216 May 5 Final Exam & Lab Checkout

Chemistry 318 - Organic II Laboratory
Syllabus – Fall 2013 Date Experiment Slayden & Stalick, 2005; Pavia, et al (2nd Ed), 2005 Aug 26-30 Check-in, NMR Video Sept 3-9 Lecture: 1. Review - IR, UV, Mass Spec 2. Nuclear Magnetic Resonance Spectroscopy (NMR) Slayden - p Solomons - pp , , , Pavia - p. Techniques 26, 27 ; pp Schornick - Sept 10-16 Bromination of Toluene (Ortho, Para Substitution) Slayden - p. 61 – 65 Sept 17-23 Nitration of Methyl Benzoate Meta Substitution Slayden - p. 67 – 69 Pavia - pp , 671, 643 Sept 24-30 Friedel-Crafts synthesis of 4,4’-de-tert-Butylbiphenyl Slayden - p Oct 1-7 NMR – NMR Spectroscopy Identification of Unknown Slayden - p. 59 – 60 Pavia - p – 964 Oct 8-15 NMR Unknown (cont’d) NMR instructions (Honeychuck) Mar 12 Spring Break - No Lab Oct 16-22 Synthesis of Grignard Reagent Pavia - p. 278 – 288 Oct 23-29 Synthesis of Benzoic Acid (Continuation of Grignard Exp) Pavia - p Oct 30-Nov 5 Qualitative Organic Analyses (Aldehydes & Ketones) Slayden - p. 73 – 76 Pavia - p. 470 – 474 Nov Synthesis of Isopentyl Acetate (Banana Oil) Pavia - pp , , Schornick - Nove 13 19 Synthesis of Dibenalacetone Slayden - p Nov Synthesis of biodiesel from vegetable oil Slayden - p. 77 Pavia - p. 207 – 216 Dec 2-6 Final Exam & Lab Checkout

Chemistry 315 - Organic I Laboratory Syllabus – Summer 2011Session A
Date Experiment Slayden & Stalick, 2005; Pavia, et al (2nd Ed), 2005 May 17 Introduction, Safety, Check-in Slayden pp. 1-12; Pavia pp 2-5; Tech 1, 2 & 3.9 May 18 Physical Properties Melting Point Refractive Index Density Slayden pp Pavia Tech pp Pavia Tech pp Pavia Tech pp Pavia Tech pp May 19 Recrystallization Filtration Slayden pp Pavia Tech pp , , 694 Pavia Tech pp Pavia Tech pp May 24 IR, MS, UV Spectroscopy Lecture Web Site Pavia Tech pp , 882, Solomon’s Sec 2.16, May 25 Spectroscopy Lecture (Con’t) Simple Distillation of Unknown Refractive Index of Unknown Infrared Spectrum of Unknown Slayden pp Pavia Tech pp May 26 Gas Chromatography: Acetates Slayden pp May 31 Distillation of a Mixture: Simple Distillation Fractional Distillation Slayden pp Pavia Tech pp Pavia Tech pp Pavia Tech pp June 1 Gas Chromatography of Distillate Mixtures Slayden pp. 39 Pavia Tech pp June 2 Synthesis: t-Butyl Chloride Slayden pp Pavia Exp pp Pavia Tech pp Pavia Tech pp June 7 Qualitative Organic Analysis: Solubility (H2O & H2SO4) Alkanes, Alkenes, Alkynes, Aromatics, Alkyl & Aryl Halides, Alcohols Slayden pp Pavia Exp pp ; ; ; June 8 Qual Org Analysis (Con’t) June 9 Final Exam; Check out

Chemistry 318 - Organic II Laboratory Syllabus – Summer 2014 Session C
Date Experiment Slayden & Stalick, 2005; Pavia, et al July 1 Check-in, Safety Video, NMR Video Slayden – pp. 1 – 20 Pavia – Tech 1 , 2, 3 July 2 Lecture: Review IR, UV, Mass Spec Lecture: Nuclear Magnetic Resonance Spectroscopy (NMR) Slayden - pp. 77 Solomons - pp – 417 Pavia - Tech 26, 27 Schornick - July 8 Bromination of Toluene (Ortho/Para Substitution on Benzene Ring) Slayden - pp. 35 – 44, 79-88 Pavia - pp. 851 – 854, July 9 Nitration of Methyl Benzoate (Meta Substitution on Benzene Ring) Slayden - pp. 89 – 92 Pavia - pp. 338 – 340,643, 665 – 671 July 10 NMR – Identification of Unknown (Simple Distillation; Phys Char; Solubililty; Density; Ref Index, NMR; IR Slayden - pp. 97 – 98 Pavia - pp – 729, 851 – 840 July 15 Unknown Identification (con’t) July 16 Synthesis of Grignard Reagent Slayden – pp. 99 – 102 Pavia – pp. 278 – 281, 286 – 288 Schornick - July 17 Synthesis of Benzoic Acid (Continuation of Grignard Exp) Slayden – pp. 99 – 102 Pavia – pp. 686 – 688, 693 – 694, 700 – 702 July 22 Qualitative Organic Analyses (Aldehydes & Ketones) Slayden – pp. 103 – 105 Pavia – pp. 446 – 458, 468 – 474 Schornick: July 23 Synthesis of Dibenzalacetone (Claisen – Schmidt Aldol Condensation) Slayden - pp. 111 – 112 Pavia - pp. 491 – 496 July 27 Synthesis of Isopentyl Acetate (Banana Oil) Pavia – pp ,686 – 688, 693 – 697 Schornick - July 28 Synthesis of Biodiesel From Vegetable Oil Slayden – pp Pavia – pp Aug 2 lab Checkout; Final Exam

Organic Chemistry Laboratory (I & ll)
Objective The purpose of the Organic Chemistry laboratory courses is to introduce the student to basic techniques used in the lab to identify and synthesize organic compounds. Experiments Chem 315 Chem 318 Melting Point O/P Electrophilic Aromatic Substitution Bromination of Toluene Refractive Index Meta Electrophilic Aromatic Substitution Nitration of Methyl Benzoate IR Spectroscopy Unknown Freidel Crafts Alkylation Alkylvation of Biphenyl IR/NMR Spectroscopy Unknown Simple & Fractional Distillation Synhesis Grignard / Benzoic Acid Gas Chromatography Of Acetates Fischer Condensation Synthesis Isopentyl Acetate Of Distillates (Mixed Aldo Condensation) Synthesis Dibenzalacetone Synthesis T-Butyl Chloride (Sn1 Nucleophilic Substitution) Biodiesel from Vegetable Oil Qualitative Analysis (Alkanes, Halides, Alcohols) (Unknown Identification) (Aldehydes & Ketones) Techniques Mass Spectrometry Melting Point Fractional Distillation Ultraviolet/Vis Spectroscopy (UV) Refractive Index Partial Elemental Analysis Infrared Spectroscopy (IR) Simple Distillation Limiting Reagent Nuclear Magnetic Resonance (NMR) Recrystallization Gas Chromatography Vacuum Filtration

Chemistry Laboratory Class Elements: Experiments (10)
Typed, Formal Laboratory Reports Quizzes Problem Set Final Exam Safety procedures Strictly Enforced Goggles Lab Coats Gloves - Latex Non-latex (Nitrile) alternatives available Suggest old jeans & shirts (chemical spills & stains inevitable No Shorts, Flipflops, or Open-Toed shoes Safety Related Conduct

Chemistry Laboratory Honor Code
GMU operates under a strict Honor Code policy Honor Code violations will be addressed by the instructor, the Department Chair, or the GMU Office of Academic Integrity, depending on the severity of the offense The following policies will be strictly enforced in Organic Laboratory. Quizzes and Final Exams given in the laboratory will be closed book. Instructor will hand out any additional resources required Lab Reports & Spectroscopy Problem Set Lab Reports and the Problem Set are considered take home exams Students may discuss freely among themselves course subject matter from the lab texts, instructors lectures, and instructor’s website notes, but not in the context of specifics regarding lab report preparation or solutions to problem set questions All students are encouraged to seek help from the instructor, regarding details of report preparation or solutions to problems

Chemistry Laboratory Honor Code (con’t)
Students are encouraged to report suspected violations of the Honor Code to the instructor Suspected violations should be reported orally and in writing to the instructor Students reporting violations should be prepared to participate in a Honor Code Hearing, if applicable Students, who are reluctant to report violations should consider the harm done to themselves and other students by students who cheat, which has a diminishing effect on grade value

Chemistry Laboratory Class Elements (Con’t): Missed labs
There are very limited provisions for missed lab sessions, especially in the summer sessions. Laboratory setup logistics severely limit provisions for making up missed lab sessions. Students can sometimes make up a lab during the same week of a given experiment (except in summer sessions). It is the student’s responsibility to anticipate and make provisions for missed labs. Missed laboratory sessions will receive a grade of zero for the report unless arrangements are made with the instructor for making up the lab work. Missed Lab Reports Laboratory reports not handed in will receive a grade of “0.” Late Lab Reports Laboratory reports are due the week following the experiment. One Week Late – 10 points deduction Two Weeks Late – 25 points deduction Three Weeks Late – Grade of “0”

Chemistry Laboratory Laboratory Process
Quizzes - Quizzes are given at the beginning of lab and last about 20 – 25 minutes. Lab Lecture - (30-45 min)) Introduction to the next experiment Review Student Questions Instructor Subjects Detailed instructions for the Experiment Pre-Lab Reports Pre-lab reports containing Purpose, Approach, References, Procedure Descriptions, and proposed Data Presentation Templates are prepared using a supplied template. The pre-lab is due at the beginning of lab and will be checked by instructor during the Quiz. Final Lab Report – The pre-lab reports are completed with experimental data, a data summary, and an analysis of the experimental results. The final lab report is submitted the week following the experimental work The Lab Report is prepared according to the detailed guide lines described in this document utilizing a Microsoft Word lab report template obtained from the web site -

Chemistry Laboratory Grades:
Reports, quizzes, exams, and the problem set are graded on basis of 100 points. Instructor defines curve for assigning letter grades. Missed assignments will receive a grade of “0”, if not submitted within 3 weeks of lab. Quizzes / Problem Set (20% of Grade) Quizzes will cover the background and theory of the experiment performed the previous week, reaction equations, procedural details, applicable computations. Any quiz may have an additional question on Spectroscopy. Problem Set (Counts as two (2) quizzes) Lab Reports (60% of Grade) The grade for each experiment is based on the laboratory report: Technical content Procedure Descriptions Results & Observations Analysis of Results, Conclusions Completeness Organization / logical structure Presentation / Neatness Final Exam (20% of Grade)

Chemistry Laboratory The Laboratory Report:
The laboratory report plays the most important role in the presentation of the Organic Lab Course. The primary focus of the Organic Lab Course is to enhance the learning of laboratory techniques and evaluation of experimental results through a comprehensive laboratory report process. The report process requires pre-lab planning, focused lab work, and a conscientious effort to effectively communicate the lab results to others in a clear, concise, grammatically and technically correct manner. Continued improvement in neatness, technical content, organization, and readability dictate the grading process as the semester proceeds. Final reports, including any charts and spectra for a given experiment, will be submitted not later than Friday of the week following the completion of the experimental data collection. In some cases, final data collection, e.g., melting points, etc., is done at the beginning of the next experimental lab session, in which case the report will be due the following week.

Chemistry Laboratory The Laboratory Report (Con’t):
During summer sessions there are three (3) lab sessions per week. The lab reports for a summer session week are due no later than Friday of the week following the experiments of the previous week. The Lab Report is graded on the basis of: Detailed adherence to the lab report template logical Organization Completeness Brevity Scientific Knowledge & Correctness Computational Accuracy Neatness Readability Pre-lab Preparation – The student uses a Microsoft Word report template (downloaded from the Instructor’s Website) to prepare a “Pre-lab Report”, which is checked at the beginning of the lab session. The “Pre-lab” report then evolves to the “Final Report” to reflect adjustments to the pre-lab procedure descriptions, inclusion and summary of the experimental results, and the analysis of the results leading to applicable conclusions.

Chemistry Laboratory The Laboratory Report (Con’t):
Results must be organized logically in the lab report using a student designed data template for each procedure within the report. Note: Each lab report consists of one or more “Procedures” (see slide 26) Results must be organized and presented in a logical manner, using tables where appropriate Algorithms, including variables, must be defined The computation of each result must be presented including the data substitution for each variable The “Results Summary” section, following the last experimental procedure, is a paragraph summarizing all of the results obtained in the experiment. Ex: the mass of the methyl benzoate reagent was g. The “Analysis & Conclusions” section, following the “Results Summary,” is a logical development of a set of arguments, utilizing selected results from the experiment, to support any conclusions arrived at as a result of the experimental process. Emphasis is placed on correct grammar and brevity. Use as few words as possible, but use complete, grammatically correct, sentences. Do not use “First Person”, i.e., I, me, my, our, etc.

Chemistry Laboratory The Pre-lab Report
The Pre-Lab is a template for the final report. It is created utilizing a Microsoft Word template down-loaded from the Instructors Website: Click on: orglabreporttemplate.doc The Pre-lab contains all the elements of the final report except the experimental data, i.e., the results, final computations, summary, analysis, conclusions. The pre-lab report will be checked by the instructor during the lab session. The components of the pre-lab consist of the following: Note: All information in the Pre-Lab Report is assumed known to the student prior to the lab session from the laboratory text resources and the Web Site notes provided by the Instructor. Name, Date, Course & Section No., Drawer No., Partner(s), if any, entered into the Header Page of the report Title of Experiment Purpose Approach – Sequential list of the procedures to be used to conduct the experiment) References – Formal citation format for both text resources & compound resources.

Chemistry Laboratory Pre-lab Report – Principal Components
Pre-Lab Report Components (Con’t) Procedures: Start each procedure on a new page Materials & Equipment (2 Columns) Procedure Description Equation Setup Templates for presentation of results (observed or computed, utilizing tables when appropriate)

Chemistry Laboratory Final Report (The Pre-Lab report is completed)
Name (Must be on all pages of report) Title (Must be on all pages of report) Purpose Approach References Procedure #1 – Procedure Name (New Page) Materials & Apparatus (2 Columns) Procedure Description, Equation Setup Populated Data Templates & Tables Final Calculations Procedure #2 – Procedure Name (New Page) Procedure #……. Summary Table of Results (optional) Summary paragraph of Results (New Page) Analysis/Conclusions – Logically derived supporting statements to justify conclusions made as to the significance of the experimental results.

Chemistry Laboratory Report Elements
Name, Date, Drawer, Experiment No., Partners, etc. on each Header page of the report Note: Instructions for entering information into the Header fields are given in the report template. Title: Short statement about the experiment, e.g., Nitration of Methyl Benzoate. Purpose: Short, concise statement of what the experiment will accomplish. The statement should include: The principle reaction involved A new technique being introduced The principal instrument(s) that will be used. Ex: The purpose of this experiment is to synthesize a carboxylic acid utilizing an oxidation/reduction reaction between Chromic Acid and an Aldehyde. Ex: The purpose of this experiment is to synthesize the analgesic Aspirin (Acetylsalicylic Acid) in an Esterification reaction between Acetic Anhydride and Salicylic Acid. Ex. The purpose of this experiment is to identify an organic compound using Boiling Point, Refractive Index, and Infrared Spectroscopy

Report Elements (Con’t): Approach: The Approach is a logical order listing, in paragraph form, of the procedures, including major steps within a procedure, that you will use to conduct the experiment. The task here is to determine what constitutes a procedure. A procedure is a logical group of steps to produce a particular result An element in the Approach would be a simple descriptive statement of the procedure to be used. ex. Determine the Mass of Benzoic Acid by Weighing. ex. Separate crude product from reaction solution by vacuum filtration. Note: Care must be taken not to include procedural details. Note: Calculations are considered to be procedures, and thus, would be elements in the Approach. ex. Adjust the Refractive Index value to the standard temperature value of 20oC.

Chemistry Laboratory Report Elements (Con’t) Approach (Con’t):
Example: Determine the Mass of the Ethanol from its volume and density. Compute the Moles of the Reagents. Setup the Stoichiometric Balanced reaction equation. Determine the Molar Ratios. Determine the Limiting Reagent. Compute the Theoretical Yield. Extract (wash) the product with Distilled Water followed by 5% Sodium Bicarbonate. Dry the product with Anhydrous Sodium Sulfate. Determine the yield. Compute the % yield of the product. Determine the Refractive Index corrected for room temperature. Obtain an IR Spectra. Determine the Mass of Formic Acid by weighing. Determine the Mass of Isobutyl Alcohol from its volume and density. Compute the Moles of the two reagents. Setup the Stoichiometric equation. Determine the Molar ratios. Determine the Limiting Reagent. Calculate the Theoretical Yield. Mix the reagents together with the Sulfuric Acid catalyst. Wash/Extract the organic layer with Sodium Bicarbonate. Separate the Organic layer from the Aqueous layer in a separatory funnel. Dry the product with Anhydrous Sodium Sulfate. Purify and determine the Boiling Point of the product using Simple Distillation. Determine the Mass of the purified product. Compute the Percent Yield of the product. Determine the Melting Point of the product.

Chemistry Laboratory Report Elements (Con't)
Reference Citations – Text A formal citation of the principal resources used to provide background information and procedural details for the experiment. The following texts are normally cited in each Organic Lab report: Slayden, S., Stalick, W., Roth, R, 2014, Organic Chemistry Laboratory Manual, 2nd Edition: Pearson Custom Publishing: 171 p. Pavia, D.L., Lampman, G.M., Kriz, G.S., Engel, .G.R., 2011, Introduction to Organic Laboratory Techniques, A Small Scale Approach, GMU Edition, Chem 315/318, Cengage Learning Reference Citations – Website URLs direct_frame_top.cgi (The above site provides Mass, IR, Proton & C-13 NMR Spectra) (The above site provides Synonyms, Physical Properties, Molecular Formulas, Structural Formulas) Other website URLs you might use.

Report Elements (Con't) References (Con’t) – Compound Citations In addition to the text references, the report requires citations for the chemical compound(s) synthesized or identified in the experiment. The following sources can be used as references: CRC Handbook of Chemistry & Physics, 84th Edition, Lide, D.R., Editor-in-chief, , CRC Press, page no., item no. Handbook of Data on Organic Compounds, Weast, R.C., Astle, M.J., 1985, CRC Press The Merck Index, 13th Edition, 2001, O’Neil, M.J. Senior Editor, Merck & Co., Inc The citation for a compound must include: Formal International Union of Pure & Applied Chemistry (IUPAC) name One Synonym (common name) Chemical Abstracts Registry Number (CAS) Publication, Date, Edition Author (Editor) Page number where compound was found. Item number of compound

References (Con’t) – Compound Citations Synonyms In many cases organic compounds have several names in addition to the formal (IUPAC) name. Use the following steps to find the formal name: Use Google search or Bing Type in the name of the compound that you are using . Wekipedia and other sites can be used to find information about your compound, including the Chemical Abstract System (CAS) Registration No. (XXX-ZZ-Y) The CAS number can be used to locate your compound in a variety of websites and printed resources that may have the compound listed by just a single or limited number of the various synonyms. Use the CAS no. to fine the formal chemical name in the Merck Index or the CRC Handbook of Chemistry & Physics – Printed version or on-line version (ChemnetBase from the GMU on-line database library)

Chemistry Laboratory Typical page from “chemfinder.com” web site containing Synonyms, CAS No., Molecular Formula, Physical Properties, Structural Info. (

References (Con’t) - Synonyms Both the CRC Handbook and the Merck Index have cross-reference tables linking the CAS No. to the compound in the properties table. In the CRC book, the item number – cross-referenced from the CAS no. – is in the first column followed by a “Name” column and a “Synonym” column. The more formal name could be in either the 2nd column or the 3rd column. In the Merck Index, the formal chemical name is usually the name in italics following the CAS No. The citation includes the following in order: Formal IUPAC Name, Synonym (1), CAS No., Reference Source, including item number in the table and the page number Example: 1,4-dimethylbenzene (p-xylene), CAS No , CRC Handbook of Chemistry & Physics, 2003, 84th ed., Lide, D.R., Editor: # 4800, p

Report Elements (Con’t): Procedures: In general, start each new procedure on a NEW page. Exceptions can be made when two (2) or more procedures and associated results can be placed on one page in their entirety without crowding. The procedure description is placed in the left column of the procedure table in the template. Applicable results for a given procedure go in the column just to the right of the Procedure description. Each procedure is setup as an individual numbered and named entity. It includes: Procedure No. & Title Materials, and Equipment (M & E) Use two (2) columns in list (bullet) format, one for Materials and one for Equipment. The Materials column includes, disposable items (capillary tubes, etc.), principal reagents and amounts used Apparatus setups need to include a detailed list of the major components (distillation head, condenser, Meltemp apparatus, Filter Flask, etc.)

Chemistry Laboratory Report Elements (Con’t): Procedures (Con’t):
Procedure Setup (Con’t): Procedure Description A short, concise, but complete, description of the experimental steps used to obtain a particular experiment result. The procedure descriptions should be an abbreviated form of the detailed instructions from the lab text, lab manual, or Web Site Notes. The student should use his/her own words, i.e., DO NOT COPY THE BOOK. The Procedure steps should be complete sentences put in list (bullet) format. If the procedure involves a computation, the algorithm is setup as part of the procedure description. Variables must be defined. The equation (derived as necessary) must be setup to represent the computational form of the algorithm.

Procedure Scenarios: If the experiment is the identification of an unknown substance, the following initial procedures are applicable. If the sample is a liquid the next procedure is to purify the sample and determine its boiling point by Simple Distillation. The second procedure in the report is the description of the purified unknown sample – solid, liquid, color, odor, etc. The next procedure for a liquid is to determine its Refractive Index, followed by a sub-procedure to correct the Refractive Index for temperature. ND20 = ND RmTemp t ( / oC) t = Room Temp - 20 If the unknown sample is a solid, the melting point is determined. Determine the relative Solubility of the unknown in distilled water. Determine the Density of the unknown relative to distilled water. Obtain IR Spectrum and NMR Spectrum

Procedure Scenarios (Con’t): If the experiment is the Synthesis of a compound, the first objective is to determine the Theoretical Yield. To do this you must determine the following in sequence: The Masses of the Reagents The Moles of the Regents The Stoichiometric Molar Ratios The Limiting Reagent The Theoretical Yield. NOTE: Each of the above items would be a separate procedure in the report.

Chemistry Laboratory Report Elements (Con’t): Procedures (Con’t)
Procedure Scenarios (Con’t) Synthesis of Compound (Con’t) If one or more of the reactants is a solid, the following considerations are applicable: Determine Mass of reactant A to the nearest g. by weighing Determine Mass of reactant B to the nearest g. by weighing Note: Since the 2 steps above involve the same process to determine the mass of the reagents, only one (1) procedure is required. Compute the Moles of reactants A & B. Note: This is a separate procedure

Procedure Scenarios (Con’t): Synthesis of a Compound (Con't): If one or more of the reactants is a liquid the following considerations are applicable: If a reactant is an Inorganic liquid, e.g., acid or base, use a Volumetric Pipet (volume precision is good to at least ml). This volume must be converted to Mass using the relationship between volume, density and mass Density = Mass / Vol Mass = Density x Vol The Mass must be adjusted for the percentage content of the solute in the solution. For example, the % Nitric Acid in conc Nitric acid is 70%. Thus, the mass of HNO3 is 70% of the mass of the solution. As an alternative, the relationship between Volume and Molarity can also be used to determine the number of moles being used (Molarity = Moles / Liter)

Procedure Scenarios (Con’t): Synthesis of a Compound (Con't): If one or more of the reactants is a organic liquid the following considerations are applicable:  The density and percentage content are usually not applicable.  Organic liquids should be weighed directly to obtain the mass to the nearest g.  Once the mass is determined, it is converted to moles. Once the Moles of Reactants have been determined, set up the Stoichiometric balanced equation and determine the Molar Ratios Determine Limiting Reagent from the number of Moles actually used in the experiment and the Molar Ratio from the balanced equation. Note: See example computations Compute the Theoretical Yield

Chemistry Laboratory Report Elements (Con’t) Results
The results obtained from the experiment are reported on the “Right” side of the report page opposite the procedure description. The format of each “Results” section must be carefully designed so that the data / observations / calculations are presented in a logical and clearly readable manner, i.e., NEAT. The results are tabulated (not discussed) in a table or other designed format. Excel tables can be imported. Procedure #1- Boiling Point Materials Equipment ___ ___ ___ ___ Procedure Description 1st bullet 2nd bullet Equation Setup Results Observations Measurements (Tables, if applicable) Calculations: Show data substitutions, units, and appropriate precision

Chemistry Laboratory Download the Lab Report Template from the Web Site Information is typed in the shaded blocks of the tables. Procedure Descriptions, Materials, Equipment are “Bulletized” Information for the “Header” table is entered as follows: Select “Header & Footer” from the “View” Menu. Enter the appropriate information into the shaded blocks. Select “Print View” from the “View” Menu The Header information will flow automatically to each page. Typical Header Table Experiment: Date: Type the Name of the Experiment Here Name Partners Drawer No. Course / Section Type Your Name Type Your Partners Names (if any) Chem 315 / 202 Typical Procedure Table Proc # 1 Type procedure Title Here Results Materials Equipment Type results of the procedure here. The Results template must be: Organized Neat Logically presented Procedures involving equations must show the computation for each result. Unknown # Q46 50 mL Erlenmyer flask Desc: Procedure Descriptions must be: Bullets Complete Sentences Full, but brief description of the process Equation Setup: Show the Equation to be used (if applicable) and define the variables. NOTE: Each Shaded Block Will Expand As Necessary To Accommodate Additional Lines Of Information.

Procedure Examples Melting Point / Refractive Index
Experiment: Date: Melting Point / Refractive Index Name Partners Drawer No. Course / Section Proc # 1 Melting Point of 2 known substances Results Materials Equipment Substance # 1 1st MP nd MP 85.4oC oC 85.2oC oC Avg: oC oC Substance # 2 93.7oC oC 93.9oC oC Avg: oC oC Capillary tubes 3 ft glass tubing 2 known compounds Meltemp Apparatus Desc: Crush small amount of dried sample on a clean watch glass. Insert about 1/4 in. sample into glass capillary tube by gently tapping sample with open end. Insert glass tube, closed end down, into a 3ft long glass tube from instructor's desk, and let melting point tube drop and bounce on desk atop Sample should move from open end to closed end. Place tube with sample in Mel Temp apparatus and slowly raise temperature until sample melts. Allow sample to solidify and repeat melting process; this time reducing rate of temperature rise even slower when temperature reaches a few degrees before sample is expected to melt. Note temperature at which sample first starts to melt and when sample is completely melted This is the melting point range. Repeat for additional samples. Equation Setup:

Procedure Examples Nitration of Methyl Benzoate Experiment: Date: Name
Partners Drawer No. Course / Section Proc 1 Determine Mass of Methyl Benzoate Results Materials Equipment Mass Vial + Methyl Benzoate g Mass Vial g Mass Methyl Benzoate g Methyl Benzoate Balance Calculator Desc: Obtain approximately 3 g of Methyl Benzoate weighed to the nearest g. Equation Setup: Vial Full – Vial Empty = Mass of Reagent Proc # 2 Compute the Moles of Methyl Benzoate Results Materials Equipment Moles MB = g / g/mole = moles MB Note: Appropriate Precision must be applied to Calculations and Results. See last page of this document for review of data precision Calculator Desc: Compute moles from the Mass and the Molecular Weight Equation Setup: Moles = Mass(g) / Mol Wgt (g/mole)

Procedure Examples Nitration of Methyl Benzoate
Experiment: Date: Nitration of Methyl Benzoate Name Partners Drawer No. Course / Section Proc 3 Determine Mass of Nitric Acid Results Materials Equipment Vol HNO3 = mL Mass MB = Den x Vol x % Comp = 1.41g/ml x 2.000ml x 0.70 = 2.04 g Conc Nitric Acid (70%) Graduated Cylinder Calculator Desc: Use Volumetric Pipet to obtain mL HNO3 Calculate Mass of HNO3 from Volume, Density (1.41 g/mL) and % composition. Equation Setup: Density = Mass / Vol Mass = Density(g/ml) x Vol(ml) x % Comp Proc # 4 Compute the Moles of Nitric Acid Results Materials Equipment Moles HNO3 = 2.04g / g/mole = moles Calculator Desc: Compute moles from the Mass and the Molecular Weight Equation Setup: Moles = Mass(g) / Mol Wgt(g/mole)

Partners Drawer No. Course / Section Proc 5 Mix Reagents and Initiate the Reaction Results Materials Equipment Conc Nitric Acid Methyl Benzoate 50 mL Beakers Stirring Rod Ice / Water Bath Desc: Place Benzoic Acid and 6 mL Conc Sulfuric Acid in a 50 mL beaker in an ice/water bath. In a separate beaker in an ice/water bath put Conc HNO3 and 2 ml Conc Sulfuric Acid. Drop wise add H2SO4/HNO3 mixture to the H2SO4/Benzoic Acid mixture stirring continuously with stirring rod. Equation Setup:

Partners Drawer No. Course / Section Proc # 6 Vacuum Filtration Results Materials Equipment Crude Product Distilled Water Methanol Filter Buckner Funnel Vacuum Tubing Spatula Desc: Isolate precipitated product by vacuum filtration using a Buckner Funnel Attach Vacuum tubing to filter flask and vacuum port on desktop. Place filter moistened with cold water into Bucker Funnel. Transfer Product to Buckner Funnel using spatula and minimal amounts of water. Allow vacuum to pull solvent through the filter. Wash product with 2 15 mL portions of cold distilled water. Wash product again with 2 15 mL portions of cold Methanol. Equation Setup:

Chemistry Laboratory Summary Discussion
The summary/discussion is a listing in “Paragraph” format of the results obtained in the experiment, i.e., ALL RESULTS. The results are not to be embellished or interpreted in any way. It is simply a summary listing of each result you obtained. Analysis/Conclusions A step by step presentation of arguments, utilizing selected results as applicable, to make a statement in support of any conclusions you have reached regarding the results of the experiment. Ex. What sequence of results lead to your selection of the identity of the Unknown compound? How did your yield compare to the calculated theoretical yield? How does Gas Chromatography determination of Mole Percent in a mixture compare to the composition as determined by Fractional Distillation? What functional groups were identified from the IR analysis and how did you decide on a particular compound structure?

Procedure Examples Nitration of Methyl Benzoate
Experiment: Date: Nitration of Methyl Benzoate Name Partners Drawer No. Course / Section Summary of Results: The results (ALL RESULTS) of the experiment are summarized here in a paragraph. Ex. The melting point of the 1st known was 67.8oC. The refractive index of the known compound was The corrected value for the refractive index raw value was The principal absorptions in the IR Spectrum were, saturation at cm-1; carbonyl at 1720 cm-1, C-O bond at 1275 cm-1. The percent yield of the product was 68.5%. Analysis & Conclusions: Develop a logical set of arguments, using selected experimental results to support any conclusions you have reached about the experiment. Note: The identity of an unknown should not be declared until AFTER the arguments supporting its identity have been developed.

Summary of Compound Properties
Use table for Experimental Unknowns & Synthesized Compounds only. Use appropriate literature resources to fill in “Literature” values, even if experimental results are not available. Literature Summary (Unknowns, Synthesized Compounds) (Do Not List Reagents) Unknown Number Name (IUPAC) Synonyms Melting Point (oC) Lit Exp Boiling Point (oC) Refractive Index (nD20) Solubility (Rel to Water) Density Rel to Water Molecular Formula Structural Formula

Chemistry Laboratory Report Grading Form
Sec Unk No. Name: Experiment: Report Segment Grade Codes Max Pts Rpt Comments Lab Report (Pre-Lab & Final) 10 Procedure descriptions, result templates Purpose 5 Brief, concise statement of what the experiment will accomplish and by what means, i.e., Principal Instrumentation, Reaction Type, etc. Approach Each Procedure gets a sentence A logically organized listing - in paragraph form - of the procedures to be used. Reference Citations Background / theory citations Compound citations, i.e., CRC Handbook, Merck Index Use formal citation format – Author(s), date, title, publisher, pages. Synthesized & identified compounds must also be referenced, including the page no. Materials & Equipment List in “Bullet” Format”, of the equipment & materials used in the experiment. Use two (2) columns: Materials Equipment Procedure Descriptions Description, in “Bullet Format” Each step in a separate bullet Use grammatically correct original language Computations Usually set up as separate procedures. Equation is setup as part of procedure description. Set up equation & define the variables All calculations must be shown and must include data substitutions and applicable units. Results must reflect appropriate precision. Theoretical Yield Applicable to experiments involving compound synthesis. Stoichiometric balanced reaction equation, molar ratio, reaction mechanism, limiting reagent, theoretical yield, summary table Results Observations, Measurements, Computations, Spectra results Organize logically, neatly. Use aligned columns or small tables when appropriate. Includes spectra absorption summary. Don’t crowd. Summary of Results Paragraph summarizing all of the experimental results obtained. Analysis, Significance of Results, Conclusions Construct logical arguments, using applicable background, theory, and experimental results to support any conclusions about the results. Literature Summary Table Summary Table: literature and experimental values for principal reagents, synthesized compounds, or identified compounds. Total Points 100 Late Penalty Final Points

Laboratory Report Grading Codes
Lab Report (Pre-Lab & Final) Code Comment a Report – not done, late, incomplete b Report Template – not used, not typed c Header Info – missing, incomplete d References – missing, incomplete e Purpose/Approach – missing, incomplete, weak f Procedure Descrip – missing, incomplete, weak g Procedure Setup – disorganized, ambiguous h Procedure Setup – crowded, start on new page i Result Templates – missing, incomplete j Reactions/Equations – missing, incomplete Purpose a Text – format, grammar, sentence structure b Text – wordy, overstated, superfluous c Text – originality, use your own words d Elements – omit background. approach items e Elements – principal reaction/equipment missing f Elements – missing, incomplete g Elements – technically weak, incorrect h Elements – disorganized, ambiguous Approach a Text – format, grammar, sentence structure b Text – wordy, overstated, superfluous c Text – not in paragraph form d Text – originality, use your own words e Elements – each element in a separate sentence f Elements – omit background, procedural details g Elements – missing, incomplete h Elements – technically weak, incorrect i Elements – disorganized, ambiguous Reference Citations a Reference Citation – missing, incomplete b Reference Citation – incorrect c URL Citation – missing, incomplete d Compound Citation – missing, incomplete e Compound Citation – incorrect f Compound Citation – page no., item no., missing g Citation Source – not citable (website, catalog) Materials & Equipment (M&E) a Format – not in 2-column “bullet” format b M&E items – missing, incomplete c M&E items – mislabeled, incorrect Procedures a Procedure No. – missing, incorrect b Procedure Title – missing, incomplete, incorrect c Procedure Title – wordy, overstated d Procedures – missing e Procedures – not used, not applicable f Procedures – disorganized, ambiguous g Procedures – need to be separated h Procedures – need to be combined i Procedure Desc – not in “Bullet” format j Procedure Desc – missing, incomplete k Procedure Desc – disorganized, ambiguous l Procedure Desc – technically weak, incorrect m Procedure Desc – originality, use your own words n Procedure Text – grammar, sentence structure o Procedure Text – wordy, overstated, superfluous p Extraneous Info – omit analysis & conclusions Theoretical Yield Code Comment a Reaction Equation – missing, incomplete, incorrect b Molar Ratio – missing, incomplete, incorrect c Reaction Mechanism – missing, incomplete, incorrect d Limiting Reagent – missing, incomplete, incorrect e Theoretical Yield – missing, incomplete, incorrect f Summary Table – missing, incomplete, incorrect Results (Includes Tables, Charts & IR/NMR spectra) a Template – weak design, disorganized b Presentation – messy, not typed c Results – missing, incomplete d Results – incorrect, ambiguous e Results – redundant, misplaced f Tables, Charts – missing, incomplete, incorrect g Spectra – missing, incomplete, incorrect h Spectra Labels – missing, incomplete, incorrect i Extraneous Info – omit background, procedure items j Conclusions – out of place, move to analysis Computations / Chemical Reactions a Equation Setup ` – missing, incomplete, incorrect b Variables – undefined, ambiguous c Data Substitution – missing, incomplete, incorrect d Computation ` – missing, incomplete, incorrect e Units – missing, incomplete, incorrect f Chem Reactions – missing, incomplete, incorrect g Precision, Sig Fig – incorrect Summary of Results a Results – missing, incomplete b Results – incorrect, don’t match report c Results – disorganized, ambiguous d Results – each result in a separate sentence e Text – not in paragraph format f Text – grammar, sentence structure g Text – wordy, overstated, superfluous h Extraneous Info – omit background, procedural details i Conclusions – out of place, move to analysis Analysis, Significance of Results, Conclusions a Analysis – missing, incomplete b Analysis – weak, incorrect c Analysis – disorganized, ambiguous d Analysis – arguments incomplete, missing e Analysis – arguments lack support data f Analysis – weak theory connection g Results – repeat of summary of results h Text – grammar, sentence structure i Text – wordy, overstated, superfluous j Extraneous Info – omit, purpose, procedural details Literature Summary Table Code Comment a Literature Summary Table – missing, incomplete b Unknown No. – missing, incorrect c Unknown Identification – missing, incorrect d Compound (IUPAC) Name – missing, incorrect e Compound Synonyms – missing, incorrect f Physical Properties – missing, incorrect g Molecular Formula – missing, incorrect h Structural Formula – missing, incorrect i Report Template – do not modify

Chemistry Lab Report - Computations
There is NO separate Calculations section. Each computation is placed in the report as a NEW PROCEDURE A Computation Procedure is created as soon as all pertinent information needed for the calculation becomes available through prior experimental results and/or other computed results. Each computation is to be setup as a separate procedure. The equation is setup along with variable definitions in the procedure description. The data substitution and final calculations are presented in the results section across from the description section. Appropriate units must be presented and the calculations must be carried out with correct precision. The student must plan and design the results section to accommodate all of the anticipated results – measured, observed, or computed - for a given procedure. New procedures should not be started until the previous procedure and associated results are completed. Computations using results from two or more procedures should be grouped and presented in a separately titled procedure as soon as all of the pertinent data for the new computation is available.

Computation Setup In the “Description” box of the Procedure section provide a brief description of the equation and what it does. Set up the equation in the “Equation Setup” box of the Procedure Section. The equation setup should define the variables used in the equation and their logical relationship. In the “Results” box of the Procedure section show the values of the variables used in the equation and then substitute the values in the equation and make the final calculation. Show appropriate units. Report results to appropriate accuracy, i.e. correct number of decimal places and significant figures. Note: When multiple computations are done using the same “Equation” only “ONE” procedure is needed. If the equation changes then a “NEW” procedure is required.

Organic Chem Lab Algorithms Many of the Organic Laboratory Reports require the student to make computations for selected results. These include: Mass of a reagent from the weight of the vial containing the reagent and the mass of the vial empty. Mass Vial Compound = g Mass Vial = g Mass Compound = g Mass of a liquid reagent (generally inorganic acids or bases) from the volume, density, and % composition. Mass (g) = Vol(mL) x Den(g/mL) x % comp/100 Moles of reagents from the Mass and Molecular Weight. moles = mass / mol wgt. The Moles of a reagent can also be computed directly from the Volume and Molarity of the reagent, e.g. the Molarity of concentrated HCL is 12 moles/L moles = Vol(L) x Molarity (moles/L)

Limiting Reagent The “Limiting Reagent” is that reactant whose mass (on a molar equivalent basis) actually consumed in the reaction is less than the amount of the other reactant, i.e., the reactant in excess. From the Stoichiometric balanced reaction equation determine the molar ratio among the reactants and products, i.e., how many moles of reagent A react with how many moles of reagent B to yield how many moles of product C, D, etc. If the ratio of moles of A to moles of B actually used is greater than the Stoichiometric molar ratio of A to B, then the A reagent is in “Excess” and the B reagent is “Limiting.” If, however, the actual molar ratio of A to B used is less than the Stoichiometric molar ratio, then B is in excess and A is “Limiting.” Example 1 A B  C Molar Ratio A:B = 1 Moles actually used: A = B = 0.698 Ratio of moles actually used (A/B): /0.698 = 0.498 <  B is in excess) & A is Limiting The theoretical yield of product will be the same as the “limiting Reagent” on a molar equivalent basis (A/C=1), i.e., moles.

Limiting Reagent Example 2 A B  C Stoichiometric Molar ratio A:B = 1 : = 1.0 Moles actually used: A = B = 0.12 Ratio of Moles actually used (A/B): 0.20 / 0.12 = 1.67 The ratio of A:B is greater than 1.00 A is in excess and B is limiting. Only 0.12 moles of the 0.2 moles of A would be required to react with the 0.12 moles of B. The reaction would have a theoretical yield of 0.12 moles of C (Molar Ratio of B:C = 1). Example 3 – Molar Ratio 1:2:1 A B  C Stoichiometric Molar ratio A:B = 1 : 2 = 0.5 Moles actually used: A = ; B = 0.023 / = <  A is limiting Only  2 = moles of the moles of B are required to react with moles of A. Since < 0.023: B is in excess, A is limiting. The reaction would have a theoretical yield of moles of C (Molar Ratio of A:C = 1).

Limiting Reagent (Con’t) Limiting Reagent Procedure Setup Alternative Limiting Reagent Determination 4 NH3(g) O2(g)  4NO(g) H2O(g) 2.00 g NH3 is mixed with g Oxygen The limiting reactant that produces the lesser amount of product (NO) is Oxygen: (3.00g vs g) Proc # 5 Determine Limiting Reagent Results Materials Equipment Stoichiometric Ratio: : 1 Ethyl Alcohol is limiting Calculator Desc: Compare stoichiometric molar ratio of reactants to the actual molar ratio If the actual ratio is less than the stoichiometric ratio, then the numerator reactant is limiting Equation Setup:

The Theoretical Yield Table (Con’t) The Theoretical Yield, in grams, is computed from the number of moles of the “Limiting Reagent”, the Stoichiometric Molar Ratio, and the Molecular Weight of the product. Yield = moles (Lim) x Molar Ratio x Mol Wgt The Percent Yield of a product obtained in a “Synthesis” experiment is computed from the amount of product actually obtained in the experiment and the Theoretical Yield. % Yield = Actual Yield / Theoretical Yield x Note: The yield values can be expressed in either grams or moles Lab Report: Limiting Reagent Procedure setup

Retention Time is the time from point of injection of a compound into a Gas Chromatograph to its elution from the column. For a given set of instrument conditions this time is constant for any given compound. Thus, it can be used to identify compounds in an unknown mixture when compared to a mixture of known compounds. The retention time can be computed using the chart speed and the distance from the start point on the chromatogram to the mid-point of the peak. Velocity = Distance / Time Retention Time = Distance / Chart Speed

Peak Area / Molar Content The Area of a peak in a Gas Chromatogram is proportional to the Mole content of the mixture. Thus, the ratio of the peak area of a given compound and the total area of all the peaks on the chromatogram gives the mole fraction of the compound. The Peak Area can be computed by the “Triangulation Method,” which is the height of the peak multiplied by the “Width” of the peak at 1/2 the height of the peak: Area = Peak Height x 1/2 peak height The Mole Fraction is computed by dividing the individual peak areas by the sum of peak areas in the chromatogram. Mole Fraction = Peak Area / Total Peak Area The Mole Percent is computed by multiplying the Mole Fraction values by 100. Mole % = Mole Fraction x 100

Thermal Response Adjustments to GC Peak Areas Mixtures of compounds will produce GC peak areas proportional to the molar content. Thus, Equimolar mixtures of compounds should produce Gas Chromatography peaks of equal area. Similarly, mixtures of any known molar content will produce peak areas in direct proportion to the molar content. Compounds with different functional groups or widely varying molecular weights do not all have the same Thermal Conductivity. This causes the instrument to produce response variations, which result in peak areas that are not in direct proportion to the molar content. Mole percent values of a mixture of unknown mole percent computed from peak areas can be adjusted for any non-linear thermal response based on the peak areas obtained from a mixture of similar compounds with a known Molar content, generally an equimolar mixture containing similar compounds in the unknown mixture.

Thermal Response Adjustments (Con’t) Correction Factors (called “Thermal Response Factors (TR)” are computed as ratios of the area of one peak in the known mixture acting as the “base peak” to the area of each of the other peaks in the mixture. Where subscript “s” refers to the “Base Peak” and subscript “i” refers to each compound in the mixture. Note: There must be a least two similar compounds in the known & unknown mixtures. The relationship between the peak areas of a mixture of compounds, the Molar Content, and the Thermal Response factors can be expressed as follows: Since the Areas of the peaks in the unknown mixture can be obtained by measurement and the Thermal Response Factors are known from the known mixture, the new corrected molar ratios can be obtained by rearranging the above equation:

Thermal Response Adjustments (Con’t) Each of the Molei / Moles values in the mixture is equivalent to the individual areas (now corrected for the Thermal Response effect) that were used to compute the “Total Area” of the peaks prior to computing the “Mole Fraction” and “Mole Percent” without the Thermal Response correction. Therefore, by adding the Molei / Moles values to get a “Total” value, the new corrected Mole Fraction can be computed by dividing each of the Molei / Moles values by the “Total” value. The new Mole Percent values are then computed by multiplying the new Mole Fractions times 100. Example: EtAc (2) ProAc (3) BuAc (4) HexAc (6) Standard Equimolar Mixture Measured Peak Area 1.44 1.09 1.16 0.98 TRs/TRi = As/Ai (s=2) = 1.00 = 1.33 = 1.24 = 1.48 Unknown Peak Area 2.14 2.18 2.12 1.54 areai/areas = 1.35 = 1.23 = 1.07

Refractive Index The measured value of Refractive Index must be corrected to a standard temperature (usually 20oC) The Index of Refraction (ND) decreases with increasing temperature, i.e., velocity of light in the medium increases as density decreases. Measured values of (ND) are adjusted to 20oC For measured temperatures >20oC, the correction factor computed below is added to the measured value because the value at 20 oC would be greater than the value at the measured temperature. Corrections for measured values <20oC are subtracted from the measured value. Temp Correction Factor t * = (Room Temp – 20) * The following equation automatically accounts for the measured temperature: ND20 = NDRm Temp t * ND20 = NDRm Temp + (Room Temp – 20) * Ex: For an observed value of at 16oC, the correction is: ND20 = (16 – 20) * = ( – 4 ) * = – =

IR /NMR Problem Set Notes
The Problem Set is a Powerpoint document that will be ed to each student. The problem answers are to be completed, i.e., typed, in the shaded boxes provided. Compound structures and materials not suitable for typing will be hand-entered in the shaded boxes. Each problem consists of one or more parts, each of which has a shaded text box in which the student provides the required information. In the Spectra problems, the student is expected to provide an analysis of the information provided for each part, i.e., Mass Spectrum, Partial Elemental Analysis, Ultraviolet/Visual Spectra, Infrared Spectra, 1H1 (proton) NMR Spectra, 6C13 (Carbon-13) NMR Spectra. The above results are then pulled together in a logical set of arguments leading to the identity of the compound, its molecular formula, and its structure. The problem set counts as two (2) quiz grades. See the next three (3) pages for notes on the analysis process. Also check the Web Site documents on the IR and NMR lecture material.

Each problem provides several pieces of information to help in the identification process. IR Spectrum (Functional Groups) 1H1 NMR Spectrum (No., Type, Location of Protons) 13C6 NMR Spectrum (No. & Type Carbon atoms) UV-Vis Molar Absorptivity (Molar Extinction Coefficient) –  & log  Conjugate systems (alternating double bonds - , - Unsaturated ketones, Dienes, Polyenes) show values of  & log  in the range:  = 10,000 – 100,000 (Log  = 4 – 5) Aromatic Conjugated Systems show values of  and log  in the range:  = 1000 – 10, (Log  = 3 – 4) Carbonyl (C=O) compounds show values of  and log  in the range:  = 30 – (Log  = 1.5 – 2.5) Nitro (-1O–N+ =O) compounds show values of  in the range:  = < (Log  < 1.0)

Mass Spectrum with Molecular Ion Peak Molecular Ion Peak represents Molecular Weight. Molecular Ion peak values that are Odd indicate the presence of an Odd number of Nitrogen atoms in the compound. Two Molecular Ion peaks with a relative abundance ratio of 3:1 indicate presence of a single Chlorine atom. Two Molecular Ion peaks with a relative abundance ratio of 1:1 indicated presence of a single Bromine atom. Partial Elemental Analysis of the Compound The percentage values given represent the percent of the compound’s Molecular Weight attributed to that element. Usually %Carbon & % Hydrogen is given. The molecular ion peak(s), molar absorptivity coefficient, and the principal functional groups from the IR spectrum provide the information necessary to identify any additional elements present in the compound. The remaining Molecular Weight after the Carbon and Hydrogen have been accounted for is divided among the remaining elements in the compound.

Partial Elemental Analysis of the Compound (Con’t) Where: nx = No. of Atoms of elements X in compound RMM = Relative Molecular Mass (Mol Wgt) RAM = Relative Atomic Mass of Element X Example Molecular Weight (RMM) = g/mol % Carbon – 62.0% Mol Wgt C (RAM) – 12.01 % Hydrogen – 10.4% Mol Wgt H (RAM) –  Now compute the remaining mass of the molecule after accounting for Mass of Carbon and Hydrogen 58.08 – ( ) = ~ 16  1 (Oxygen)  Molecular Formula – C3H6O

Approximate Numbers and Significant Digits
Some numbers are “Exact” or “Pure”, i.e., having been defined or counted. Examples: 3 Cherries, 125 People, 50 Measurements, 16 oz in a pound Most numbers involved in technical and scientific work are obtained through some process of measurement. All measurement processes are imprecise, i.e., only approximations of the true values. The precision of an instrument dictates the relative accuracy of the values that can be reported, i.e., the number of significant digits. The precision of a number refers directly to the position of the last significant digit relative to the decimal point. All none zero digits are significant. Zeros other than those used as placeholders for proper positioning of the decimal point, are also significant. There is uncertainty in the last significant digit. For example: A person records his weight on a scale to be 160 lbs. The last “zero” is a placeholder and is not significant. Thus, the “6” has uncertainty. His true weight could be 158 lbs, 161 lbs, lbs, lbs. etc. When multiplying or dividing groups of measured values the answer will have the same number of significant digits as the least accurately known number. When adding or subtracting numbers, the answer is significant only to the fewest number of decimal places contained in any of the numbers being added or subtracted, i.e. significant to the least precise number. Number Significant Digits No decimal point; therefore last two zeros are not significant, i.e., placeholders The uncertainty is in the last significant digit, i.e. the “6” Five significant figures; the 3 zeros are significant; the “4” has uncertainty. significant figures; precision is defined to the fourth decimal significant figures; the zero after the decimal is a placeholder Precision is defined to the third decimal, thus all zeros here are significant The uncertainty is in the last zero Zeros to the right of the decimal are used as placeholders for decimal point Precision is defined to the fourth decimal. Precision defined to the second decimal; thus all digits significant Precision is defined to the third decimal; thus all 4 digits are significant. The uncertainty is in the last “zero” Precision is defined to the second decimal, thus all five digits are significant 25 x = not 292.5 16.5 / = not = not 7.71 x = ( ) = ( ) = 2000 7.71 x x (1/180.5) x = (0.008 x x 2000) = ( x 2000) = 0.1 (0.066 x 39.82) / ( 1.43 x 8.61) = (2.6 / 12.3) = 0.21

Citing Chemical References
CRC, Handbook of Chemistry & Physics, , 80th Edition, ed. D, Lide, Boca Raton, Fl: CRC Press, Inc. CRC, Handbook of Data on Organic Compounds, Vol I, A-O, Vol II, P-Z, 1987, eds. R.C. Weast, and M.J. Astle, Boca Raton, Fl: CRC Press, Inc. Merck & Co., Inc. The Merck Index, 1996, 12th edition, Eds. S. Budavari, M.J. O’Neil, A. Smith, P.E. Hechelman, and J.F. Kinneary, Whitehouse Station, N.J.: Merck & Co. Inc, 1996 Dean, J.A., ed. Lang’s Handbook of Chemistry, 14th ed. New York; McGraw-Hill, 1992 Note: When citing a reference for a specific compound, include the page number where you found the compound. Online Sources Note: These resources are not citable as formal references (The above site provides Mass, IR, Proton & C-13 NMR Spectra) (Chemical Properties) GMU Library databases Click on : research databases Chemistry Knowitall U Note: To use Knowitall U, you must login to register and get code Chemistry Department Web Sites (Dr. Schornick Web Page) (Department Web Page) (Organic Chemistry) (Chem 315 Lab) (Chem 318 Lab) (General Chemistry Lab)

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