Chem lab report

Grading Guidelines

Investigation 11: How Much Acetic Acid is in Vinegar?

(2-week version)

General

· Report is due by next week on:_________________. Late lab reports will not be accepted.

· One copy of the report per group (hard copy only).

· Attach the contribution sheets to the end of the report, 1 per group member.

Formatting (points can be deducted if these items are not followed)

· Title page with Investigation name, date, lab section, group number, group members’ names, TA’s name.

· Must be written in third person, past tense, passive voice; no use of first person, and no contractions or slang. Uniform in spacing (double space) and fonts,

· Label each of the sections listed below, bold or underlined.

· Use proper grammar and spelling. Use superscripts and subscripts for chemical formulas and scientific notation. Remember to put a zero in front of the decimal point.

· Include all bibliographic entries of all reference material used.

Introduction (2pts)

· Brief description of the goal in this experiment

· Standardization, titration technique, etc.

· Brief explanation of the chemistry (acid-base reaction) and the titration process.

· Oxalic acid/NaOH, Acetic Acid/NaOH

· Give examples!

Procedure (1.5pts)

· Provide a clear description (in a paragraph style) of the procedures used during the course of the experiment; include concentration/volumes of solutions. This should be detailed enough that another group could duplicate your work.

· Molarities of solutions must be listed correctly.

· Proper subscripts and physical states are very important.

· Materials should be incorporated into your procedure, NOT simply listed out.

· Ex. 20 mL of NaOH was obtained in a 100 mL beaker.

Results (2pts)

· Include all data (even if you think it is bad). Present the obtained results in a clear and well organized fashion (tables, charts, etc.).

· Include balanced chemical equations:

· Properly use of subscripts and physical states.

• Show an example of calculations (use proper units, e.g., grams, moles, and ml where appropriate) of the following:

· Determine the molarity of NaOH through standardization.

· Determination of density of vinegar.

· Determination of acetic acid molarity in vinegar as well as mass percent.

· Results should include minimal text, any analysis should go in the Discussion.

Discussion (3pts)

· Discuss possible errors and limitations in the procedures.

· Explain your results, what does your data mean?

· Why do we need masses of the vinegar sample instead of volumes?

· Why do we need to prepare a standardized NaOH solution?

· Specifically discuss your observations

Conclusions (1.5pts)

· Restate the purpose/goal of the experiment.

· Briefly summarize the results.

· Because vinegar is usually labeled as 5% acetic acid, discuss your average result in terms of the % error. Support your recommendation to improve the accuracy in the results.

References: This is the final section in your lab report and should contain the bibliographic entries of any and all reference materials used in the writing of your lab report.

DUE: _________

(@ the beginning of Lab)

Make sure all contribution sheets are attached to the back of the Lab Report