• The use of word processors and spreadsheets is strongly encouraged for preparation of lab reports.
• Safety goggles must be worn at all times.
• No shorts, short skirts, sandals, or open- toed shoes are allowed in the lab.
• If you want to keep them in good condition, no expensive watches, calculators, or jewelry should be brought into the lab.
• Contact lenses are discouraged.
• Neatness counts.
• One staple is sufficient.
• Every sheet in your lab reports should have your name and the experiment number in the top right hand corner.
• If you plan to re-sell your laboratory textbook at the end of the semester, make photocopies of the Pre-Lab, Post-Lab, and Data Sheet pages (before each lab meeting), rather than tearing out and submitting the original book pages.



Pre-Labs (to be turned in prior to the start of class)

Your T.A. will check your pre-lab write-up for each experiment at the beginning of the lab meeting, and will return it before the end of class.  It is your responsibility to ensure that you do not leave at the end of class without your pre-lab.  You will attach the pre-lab sheet(s) to the post-lab write-up.  Pre-labs attached to post-lab write-ups without your T.A.'s initials will not be accepted for a grade with the post lab. Changes, alterations, or additions to the pre-lab will not be allowed after the class period has begun.  You may keep a copy of your pre lab to perform the lab. 

Pre-Lab Format and Guidelines

• Title page
• Abstract
• Experimental
• Pre-lab questions and answers



Title page will include:

•   your name
•   the name and number of the experiment
•   the date
•   the unknown number, if applicable (add after attaching to the completed report)



Abstract will include:

•  a statement listing the chemical principles explored in the experiment  (this is meant to outline your discussion)


Example:

The experiment will explore acid base reactions, Le Chatelier's Principle, and the Laws of Multiple Proportions and Constant Composition.


• a very brief synopsis, not a repetition of the procedure, of the experiment


Example:

Lead iodide will be prepared.  The percent yield of lead iodide will be calculated prior to analysis by the gravimetric method.  Finally the lead will be recovered and recycled.


• a statement of how you determined the success of the experiment and what criteria you will use to determine if the experiment was successful (this is meant to outline your conclusion)


Example:

The experiment will be considered successful if the experimentally determined molecular weight for magnesium oxide is within 10% of the accepted value.


Experimental will include:

1. Those things you will need later to write your lab report
2. Balanced Stoichiometric Equations that describe the reaction chemistry explored in the lab
3. Mathematical Formulas to be used for all calculations
4. A table of reagents used with appropriate physical constants


sources of these constants (chemical formula, common name, molecular weight, melting point, boiling point, density, etc) can be found in your text, The Merck Index, The CRC Handbook of Chemistry and Physics, the Martindale's Reference Desk link on the web page, and an assortment of manufacturer's product catalogs such as Sigma and Aldrich.  The source of the data must be cited.

Example:




Common  Name	Chemical  Formula	MW  (g/mol)	mp  (oC)	bp  (oC)	d25 (g/mL)
Water	H2O	18.02	0	100	.975
Acetone	CH3COCH3	58.08	-94	56	.785
Toluene	C6H5CH3	92.14	-95.159	110.8	3.14


data from Hazardous Chemical Database, The University of Akron,
Department of Chemistry http://ull.chemistry.uakron.edu/erd/



5. A list of materials and equipment (no chemicals, these appear in table mentioned above.)
6. A diagram of the assembled experimental apparatus (There is always something to draw)
7. A numbered step by step procedure written in third person, past tense, passive voice

Example:

Step 1.  Approximately 200 grams of lead carbonate was weighed into a 25 mL Erlenmeyer flask to which was added 5 mL of dilute (6 M) HCl and 5 mL of distilled water.
Step 2.  .....



Pre-Lab Question Solutions

 
All the questions, with answers (unless otherwise notified)

 

Post-Lab Write-ups

A report will be submitted for each experiment performed.  Reports will contain the following sections:

•  Reduced Data
•  Calculations
•  Discussion
•  Conclusion
•  Post Lab Problem Solutions
•  Appendices



Data will include:

•   A table of your results (must be in tabular format, reduced data only)

   Significant figures will be observed
   All units should be listed
   Appropriate labels should be used

   Each entry into your lab notebook must also meet these requirements

 
 Calculations will include

• All work for a representative problem of each calculation type if performed by hand.
• Start with the equation being used
• Include a list of the knowns
• Identify the variable to be determined
• Include all units
• Leave white space
• Box or highlight the final solution for quick reference
• Calculations performed using spreadsheets should be neatly arranged, not crowded, and include the equation, the data set, and the result either highlighted or boxed.  All requirements must be met aside from the first, as the spreadsheet does this for you if done correctly.  You can print out a page showing the formulas used in each cell, but the cells must be in logical placement (that is, the first cell corresponds to the address A1, and so on).

Discussion

The discussion should be approximately one page, have one inch margins, and be double-spaced to allow for written comments.  

• Brevity and conciseness is rewarded.
• Demonstration of critical thinking and comprehension of the chemical principles will be rewarded.
• Discuss how and where each of the principles you listed in the abstract were demonstrated in the experiment.   Include balanced stoichiometry equations and mathematical formulas where appropriate.
• Describe why something was done in a particular manner or sequence.   Reaction conditions are very important to the success of any experiment.  Temperature, time, volume, pressure, handling, molar ratios, pH, presence of catalysts, and other elements of the "recipe" are important. This factors into your error analysis.
• If possible, explore the chemistry of the experiment.  Anyone can follow a recipe, but this does not mean the person understands why the result was successful or even reasonable.
• If the result is unreasonable or if the experiment is not a success, you should be able to relate in chemical principles why this is so and provide a plausible alternative, if possible.
• Do not repeat the steps of the experiment unless it is important to a chemical point you are trying to make.

Conclusion

A very brief statement as to the success of the experiment and the results you used to support this claim.  The final answers (numbers)  using significant figures and standard deviations are necessary.

No more than two or three lines total are usually necessary.
Report numerical results with standard deviation and units and gauge their relevance to success.

xxx.xx + 0.xx grams/mole.


Report percent relative standard deviation %RSD

(recall: %RSD = standard deviation / average)


Example: 

The experimentally determined value for the molar volume of a gas was 21.5 + 0.3 L mol^-1 with a 1.26 % RSD and a 4.1 % error.  The precision and accuracy were good.  The experimentally determined atomic weight for the unknown metal, identified as Zn, was 67.3 + 0.3 g mol^-1 with a 0.42 % RSD and a 2.8 % error.  The precision was excellent and the accuracy was good.  The experiment was a success.
 

Post-Lab Question Solutions

 
All the questions, all the answers unless otherwise notified

Any emails to your T.A. regarding the post-lab questions will be answered to the whole class.  Many of the questions are structured to require research above and beyond what is learned in the manual.

 

Appendices

• Yellow pages from your lab notebook containing observations and recorded values
• Graphs -- One graph per page sized to fit the page.  Axes must be labeled appropriately with units.  A title sufficient to identify the graph should it be detached from the report must be included.
• Large raw data sets.  Occasionally there will be large data sets that need to be compiled.  Your T.A.  will let you know when this is the case.  The data set appearing in the Data section of the the report will be the reduced set.

Notebook


A carbonless, or carbon paper duplicate pre-numbered page notebook is required.  You will record all measured values and observations in this notebook.  The perforated pages will be turned in as appendices to your report.

Make-up labs

Make-up labs are available only for a University-excused absence or illness.  In this case, contact both Dr. Frank Kolar and your T.A.

 

Grading

Although the various experiments have differing contents and requirements, the following approximate point breakdown will be used in grading experiment reports:

Title page and abstract		1 point
name, date, title	0.1 points
chemical principles	0.3 points
experiment synopsis	0.3 points
success criteria	0.3 points
Experimental		2 points
stoichiometry equations	0.4 points
mathematical equations	0.4 points
reagent table	0.3 points
materials list	0.3 points
diagram	0.2 points
procedure	0.4 points
Data		2 points
reduced data table	0.4 points
significant figures	0.2 points
units	0.2 points
labels	0.2 points
Calculations		4 points
prelab problems	1 point
postlab problems	1 point
example of each	1.5 points
graphs	0.5 points
Discussion		4 points
chemical principles	1 point
applied observations	1 point
logical conclusion	1 point
overall understanding	1 point
Conclusion		1 point
results summary	0.3 points
statistical reporting	0.5 points
success or not & why	0.2 points
Notebook		1 point
raw data table	0.4 points
observations	0.4 points
unknown number	0.1 points
signatures	0.1 points
	Total:	15 points


Grading of the 25-point reports for the two-period experiments will be similar to that shown above, except that the Experimental and Data sections will be worth 4 points each, instead of 2, and the Calculations and Discussion sections will be worth 7 points each, instead of 4.

Reports submitted after the due date will be considered late and will be graded according to the following equation:

Grade = G x (3/4)^{0.2 n} 

where G is the grade that the report would have received had it been submitted on time, and n is the number of days that the report is late.  Late days will be counted based on 24 hours after reports are due, which is at the beginning of the lab period.

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Last Updated August 24, 2009  by Michael Rosynek