CHEM 212 Lab Instructions
Formatting of The Report: Labs will require some or all of the components listed below. Labs must be
submitted using the precise format outlined below on carbonless copies from your lab notebook. Each
section much be in the prescribed order with the heading written in large text and underlined.
Deviations from the format will result in a significantly reduced score. In addition, a horizontal line should be drawn in between sections to clearly identify a transition to the next section.
Turning In Your Lab Report:
Each lab report will have three major parts 1) Pre-lab, 2) Data, and 3) Report I. Pre-lab: Due at the beginning of lab period.
Dr. Lemieux will provide a grading sheet to attach to the top when turning it in. The pre-lab will be checked for completeness during the lab period and returned before the end. Students with missing or incomplete pre-labs may be excused from the lab with a score of 0.
II. Data: Due at the end of lab period.
You will staple the data to the pre-lab and grading sheet and hand in before you leave. This is proof of completion of the lab and will be worth a significant number of points.
III. Report: Due the beginning of the next lab period.
Each part of the lab report must be turned in on time as specified above. Late lab reports, although accepted, will receive a significant point reduction.
I. Pre-lab
Objective: In paragraph form, using complete sentences and your own words, state the goal(s) of the
experiment. This section is expected to be relatively concise (2 to 3 sentences), but should be clear as to what you are attempting to do and how you were planning to do it. All the other details will be
contained within other sections of the lab report. A proper objective must contain the following 2 components:
a. A statement of what you are attempting to measure, determine and/or the substance that you will attempt to synthesize.
b. The key techniques and/or reactions that will employed in order to complete the measurement or synthesis.
Reaction(s)/ Structural Formulas: This section contains the balanced chemical reaction(s) performed or
Important Physical Properties: Here you should make a table that contains physical properties of
relevant reactants, main products, potential side products, solvents, or other substances involved in the experiment. These properties may include density, melting point, boiling point, molar mass, state of matter, color, specific rotation, refractive index, solubility in water, dipole moment, and others. This data must be in tabular form in this section of the lab report. Data not in this form will earn zero points for this section of the report. I will not state exactly which physical properties are important to include in preparation of each experiment. Figuring these out is an important part of the experiment and your training in scientific research.
Procedural Flowchart: This should not look like a block of text. You should use drawings and shorthand
where ever possible to most easily read what you need to do quickly. Quantities of each substance to be used should also be included. Where the experiment involves a synthesis, separation scheme should immediately follow. See the example in lab manual, Technique 2, of a separation scheme. Procedures that are not in flow chart for or do not include drawings will be assigned a score of 0 points.
Sketches: Pictures of glassware and hardware can be found in the lab textbook. A sketch of the
apparatus set- up is to be included in this section with the names of the individual components clearly labeled on the drawing. If an assembled apparatus is used, then the sketch of this combined glassware must be shown, not just the individual components.
Pre-Lab Calculations should be included here when assigned.
II. Data and Observations
Tabulated Data: As part of the prelab, you must set up a data table in this section that neatly organizes
all expected data from the experiment (masses, % yield, mp, bp, etc.). However, be sure to use a separate notebook sheet from the pre-lab so that you can turn in the pre-lab section separately.
Physical Observations: During the experiment, detailed handwritten notes are to be taken during lab
directly in your notebook, such as the color of reagents, appearance of chemical reactions or changes, density differences, actual amounts of reagents used, actual times and temperatures involved, instrumentation parameters, and all other data and observations (including any problems with
particular samples). All experiments should have some observations written down in full sentences. It is better to err on the side of too much detail with the information that you record, rather than not enough. Use passive voice (past tense, 3rd person) for recording observations.
Graphs and/or Spectra: In addition, any data printouts from instruments (e.g., spectra, chromatograms)
must be carefully annotated in the way presented in class, which means that all major peaks are
assigned in the final report. For IR, you are required to note the specific transition (e.g., sp3 C-H stretch) for all relevant structural features of the molecule. Since you might only have one copy of these, they may also be kept for analysis while writing the report and attached to the very back of the report.
III. Report
Calculations: All data treatment, calculations, and final results are to be written in the notebook. For
percent yield, you must show the full stoichiometric calculations for the theoretical yield, as well as the final calculation for percent yield. Remember to indicate the correct number of significant figures (yep, we’re still doing that :P) Where the same calculation is repeated, showing one example of the
calculation is sufficient.
Discussion and Conclusions: This section must be written in paragraph form using complete sentences
(past- tense, 3rd person). In the first sentence(s) of this section, state the final results of the experiment, including numerical values and a comparison to true or accepted values (include a quantitative analysis, such as percent error, if relevant). State if the objectives were met, and if not, why not. Be sure to always include a discussion of percent yield (Was it acceptable? Was it too low? Why?).
Include possible sources of error, and how to minimize these in the future (think about the limitations of instrumentation used, protocol, etc.). All experiments have error. Remember, the word “error” in science does not refer to mistakes but instead to the limitations of the potential accuracy of your method and tools. Address this section on errors by consulting your detailed observations and assessing what happened at each step…your proposed sources of error should emerge from these observations. Do not include human error, such as incorrectly reading a graduated cylinder or making mistakes with calculations or significant figures. Also, do not generally state that one needs to be more careful in the future…it is assumed that you are always as careful as possible with your laboratory work. Mention specific experimental improvements that would help to minimize specific error.
Example Experiment and Report
Synthesis of Acetaminophen 6/23/16
I.Pre-lab
A. Objective
Acetaminophen will be synthesized by reaction of salicylic acid and acetic anhydride. The product will be characterized by taking an IR spectrum and determining the melting point.
Experiment 1 Report Outline I.Pre-lab
A. Objective
B. Molecular structures
C. Relevant physical properties (remember to neatly arrange in a table)
D. Procedure flowchart (be sure to include primarily drawings and sketches wherever possible) II. Data
A. Part A Data (prepare a table for data before lab on a page separate from pre-lab) B. Part C Data
C. Physical observations (completely log all of your observations using complete sentences) III. Report
A. Calculations
i. Density (d = m/V, determine for hexane and water) ii. % error of density from true values
B. Conclusion
i. Statement of result (objective met?) ii. Error analysis
1. Quantitative (analysis of percent error, comparison of sig figs of various measurements)
2. Qualitative (what’s steps in the procedure or tools used contributed to increasing %error and estimate of relative contributions to % error)
CHEM 212 Exp 1 Grading Sheet Name_________________________________
Section Points Possible Points Earned Pre-lab
Objective 2
Molecular structures 1
Physical Properties 1
Procedure flowchart 2
Sketches 1
Data and Observations
Ex. 1 Part A Data 2
Ex. 1 Part C Data 2
Physical Observations 1
Report
Calculations (Density/ % error) 4
Conclusion: statement of result 1
Error analysis 3