please answer the theoretical yield and percent…
please answer the theoretical yield and percent yield and do the experiment report as mention in the General guidelines for written lab reports
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General Guidelines for CH 111L / 112L Written Laboratory Reports
The purpose of this laboratory report is to provide the student experience in writing reports
similar to reports made by scientists and engineers to their supervisors and to the scientific
community (via journal articles).
As a professional in the working world, you will be expected to have good communication
skills. When you issue a report or memo which contains typographical, punctuation or
grammatical errors, it reflects poorly on your command of the English language as well as your
professional ability. For these reasons, student laboratory reports must be error free.
When writing an important report or letter, write a draft of the document and set it aside at least
over night. Then, read it again the next day. Try to read it as if you had never seen it before. Be
certain that it conveys exactly what was intended. Typographical errors will be more apparent
the next day.
Normally, reports and memoranda are typed single-spaced. However, this report of yours
should be typed or word-processed, double-spaced. Use one-inch margins and a 12-point font
size. It is unnecessary to number the pages of the report. In order to avoid omissions, it is a
good idea to reexamine the laboratory procedure before writing the report.
Do not put reports in plastic report covers (just staple). Be sure to attach a copy of your
laboratory notebook sheet(s) with your experimental observations.
Each report should have all of the sections shown below (if applicable), in the order shown.
Except for the cover page, use the headings shown below to indicate the beginning of a new
Please note that as you take more advanced chemistry courses you will incorporate the use of
instrumentation and other types of equipment. As the complexity of the laboratory experiment
increases, so does that of the laboratory report.
Include title of the experiment, your name, and the date of the report.
Give a brief description of the background and significance of the substance you are synthesizing
or analyzing, and use brief statements to summarize the purpose of the experiment. The
introduction should usually be no longer than five or six sentences.
Describe in some detail how you performed the experiments. This section should contain
sufficient detail so that someone else could reproduce the experiment, using only the report.
Sample preparation and glassware cleaning is normally described, but routine operations (e.g.
cleaning) should be mentioned only briefly. Too much detail is redundant. For example, a
statement such as, “All glassware was washed with soapy water and triple rinsed with tap water
and distilled water.” is sufficient and would not need to be repeated throughout the report.
Data and Calculations
Include in this section all raw data collected during the experiment, whether it is numeric or in
the form of qualitative observations. All data should appear in this section, not in an appendix at
the end of the report. Tabulating data in clearly labeled tables is recommended. If it is not
possible to express a calculation electronically, it is acceptable to write it in by hand. If this is the
case, be sure to use neat and legible handwriting.
Discussion and Conclusions
Present the results of the experiment and discuss their significance. This section might include a
thorough explanation of the thought processes used in identifying unidentified samples or a
suggestion as to why your synthetic yield was so, for example. It will be expected that you will
be able to draw conclusions based on the data taken.
Additional Guidance and Common Mistakes to Avoid
1. When writing lab reports for this course, always use third person, past tense, passive voice.
Incorrect: I used an atomic absorption spectrometer to analyze sample # 90-37-1. (First
person active voice is used.)
Correct: An atomic absorption spectrometer was used to analyze sample # 90-37-1.
(Third person passive voice is used.)
2. Do not use contractions.
3. Avoid the use of the word “run” when referring to samples or standards. Samples don’t
run anywhere. Use the word analyze or a synonym.
4. Avoid paragraphs that jump from one topic to another. Each paragraph should cover one
5. Avoid the use of "who" and "whose" and other possessive forms with inanimate objects.
6. Avoid the use of "due to the fact that...". Why write all of that when you mean "because"?
7. Avoid the use of the phrase "was done". It just does not sound professional. Often "was
performed" or "was accomplished" can be substituted, although other phrases are
8. Do not use abbreviations or unusual symbols without defining them; you only need to
define it once in your report. This is especially irritating when the same abbreviation is
used repeatedly without a prior definition.
Incorrect: The AA was used to analyze the samples.
Correct: The atomic absorption spectrometer (AA) was used to analyze the samples.
9. Avoid "dangling prepositions". The easiest way to rewrite the sentence is to rearrange the
latter part of the sentence and insert a “which”. This will many time result in a sentence
that you would not use in conversation, but remember that formal written English many
times differs from informal spoken English.
Incorrect: Reagent was added to the beaker that the precipitate came from.
Correct: Reagent was added to the beaker from which the precipitate came.
10. Units of measure such as grams and milliliters (and pounds and dollars) are considered
collective singulars. They require singular verbs.
Incorrect: Exactly 4.867 g of reagent were added to the sample.
Correct: Exactly 4.867 g of reagent was added to the sample.
11. Units of measure must be separated from the preceding number by a space.
Incorrect: The instrument cost 5,000dollars .
Correct: The instrument cost 5,000 dollars.
Incorrect: The benches were separated by 5ft .
Correct: The benches were separated by 5 ft.
12. The names of chemical compounds are not capitalized. They are not cities or people!
13. Do not refer to instruments as machines. An instrument is a device used to make precise
and accurate measurements. Use that definition to distinguish between instruments and
14. “It’s” is a contraction of “it is”. The possessive form of “it” is “its”.
Incorrect: A sample was identified based on it’s IR spectrum.
Correct: A sample was identified based on its IR spectrum.
15. The term “unknown” is often used in academia when referring to a sample of
undetermined composition. This is a very artificial term, and in the “real world”, all such
samples are called “samples”. The latter is the term that students are expected to use in
16. Differentiate between the terms “determine”, which means to quantify, and “identify”
which is more qualitative in nature.
Incorrect: Determination of the identity of a liquid sample.
Correct: Identification of a liquid sample.
17. Do not confuse the terms "clear" and "colorless". You can have a clear solution that is not
colorless and vice versa. “Clear” means “without cloudiness”. “Colorless” means “without
Numbers and Symbols
18. Do not start a sentence with a numeral. This rule seems awkward at first, but with a little
experience, sentences can usually be rewritten to avoid the use of a numeral at the
Incorrect: 2.4856 g of sample was weighed into a 250-mL beaker.
Correct: A 2.4856-g portion of sample was weighed into a 250-mL beaker.
Incorrect: 10 drops of reagent were added to the sample.
Correct: Ten drops of reagent were added to the sample.
Correct: A 10-drop portion of reagent was added to the sample.
Note that a sentence can begin with a number but not a numeral.
19. When describing glassware, a dash is required between the volume and unit of volume.
Incorrect: The sample was transferred to a 250 mL beaker.
Correct: The sample was transferred to a 250-mL beaker.
The rule applies any time the volume is used as an adjective.
Incorrect: A 25 mL portion of reagent was added to the sample.
Correct: A 25-mL portion of reagent was added to the sample.
The rule does not apply to volumes of liquids when they are not used as an adjective.
Incorrect: The solution was diluted with 25-mL water.
Correct: The solution was diluted with 25 mL water.
20. The symbol for milliliter is mL, not ml or ML, etc.
21. The symbol of mole is mol, not m (meter) or M (molar). The symbol for millimole is
mmol, not mm (millimeter).
22. A decimal number that is less than one should always have a leading zero.
Incorrect: Approximately .250 g of iron wire was weighed into a 250-mL beaker.
Correct: Approximately 0.250 g of iron wire was weighed into a 250-mL beaker.
23. Use superscripts and subscripts where appropriate.
24. Spell out any whole number less than ten.
Incorrect: A total of 6 spectra were acquired.
Correct: A total of six spectra were acquired.
Correct: A total of 20 samples were analyzed.
25. Avoid the use of words such as "next" and "then" when describing the order of the
procedure. It is assumed that the order of the procedure was as stated. Remember that you
are trying to write an accurate, concise and easy to understand account of what happened.
You are not trying to write great literature.
Gaunder, R. G. University of North Alabama, Florence, AL. CH 321 Syllabus F07, 2007.
University of Waterloo Library Library Subject Guides – Chemistry Page.
http://www.lib.uwaterloo.ca/discipline/chem/acs_ref.html (accessed August 19, 2008).
Weisenseel, J. W. Instrumental Analysis Laboratory Experiments, Shearer, J. W., Ed., University of North Alabama,
Min Pages: 2
Level of Detail: Show all work
Other Requirements: 2 pages please