C125/C126 FORMAL LAB REPORT FORMAL LAB REPORT, General A formal lab report is required in conjunction with some of the experiments in each chemistry course. It is your chance to demonstrate to your professor or TA how well you understand the experiment and the chemical principles involved. A formal report is different than a term paper. It should be written in a scientific style, which is not the same style used for English or philosophy papers. The keys to effective technical writing are organization, brevity, clarity, and an appreciation of the needs of the reader. You must write clearly and be thorough, but concise. Do not ramble. The best way to avoid rambling is to first prepare an outline of the report and stick to it. Always use complete sentences. Bulleted lists are okay in a lab notebook but are unacceptable in a formal report. Formal reports must be typed. Use 1.5 line spacing, 1-inch margins, 12 pt font and 8.5x11 inch paper. Only use third person, past tense. Also, proofread well. The general structure of a formal lab report follows that of a scientific paper. It is: Title and Author (s) Introduction Experimental Information Data and Calculation Results and Discussion Conclusion References Results and discussion sections are combined into one single section. Different instructors may have specific formats that they want you to follow. You should always defer to the instructions given to you by your course. Presented here are general guidelines for writing formal lab reports and scientific papers. Before writing your first report, visit the library and examine several journal articles. Pay close attention to the style of the prose and the contents of each particular section. Several common journals to investigate are: The Journal of the American Chemical Society The Journal of Physical Chemistry Analytical Chemistry Biochemistry Initialed and dated laboratory notebook pages of the experiment must be submitted. While report sheets may be a joint effort, formal reports must be individually written. A schedule of reports and dates on which they are due is given in the course laboratory schedule. We highly recommend that reports be completed prior to the day of submission to allow time to proofread, and thus avoiding loss of points due to last minute problems. Lost data or the inability to print reports is not acceptable excuses for incomplete or missing reports. You will be informed when notebook pages will be collected before the report is due. FORMAL LAB REPORT - Title and Author(s) State the title of the experiment, your name, the date and your laboratory section number, if applicable. Also state the name of your lab partner(s). This information should be at the top of the first page. FORMAL LAB REPORT – Introduction The Introduction states the purpose of the study and introduces the reader with new ideas and topics. It also provides any background necessary to acquaint the read.

1. C125/C126 FORMAL LAB REPORT
FORMAL LAB REPORT, General
A formal lab report is required in conjunction with some of the
experiments in each chemistry course. It is your chance to
demonstrate to your professor or TA how well you understand
the experiment and the chemical principles involved. A formal
report is different than a term paper. It should be written in a
scientific style, which is not the same style used for English or
philosophy papers.
The keys to effective technical writing are organization,
brevity, clarity, and an appreciation of the needs of the reader.
You must write clearly and be thorough, but concise. Do not
ramble. The best way to avoid rambling is to first prepare an
outline of the report and stick to it. Always use complete
sentences. Bulleted lists are okay in a lab notebook but are
unacceptable in a formal report. Formal reports must be typed.
Use 1.5 line spacing, 1-inch margins, 12 pt font and 8.5x11 inch
paper. Only use third person, past tense. Also, proofread well.
The general structure of a formal lab report follows that of a
scientific paper. It is:
Title and Author (s)
Introduction
Experimental Information
Data and Calculation

2. Results and Discussion
Conclusion
References
Results and discussion sections are combined into one single
section. Different instructors may have specific formats that
they want you to follow. You should always defer to the
instructions given to you by your course. Presented here are
general guidelines for writing formal lab reports and scientific
papers.
Before writing your first report, visit the library and examine
several journal articles. Pay close attention to the style of the
prose and the contents of each particular section. Several
common journals to investigate are:
The Journal of the American Chemical Society
The Journal of Physical Chemistry
Analytical Chemistry
Biochemistry
Initialed and dated laboratory notebook pages of the experiment
must be submitted. While report sheets may be a joint effort,
formal reports must be individually written. A schedule of
reports and dates on which they are due is given in the course

3. laboratory schedule. We highly recommend that reports be
completed prior to the day of submission to allow time to
proofread, and thus avoiding loss of points due to last minute
problems. Lost data or the inability to print reports is not
acceptable excuses for incomplete or missing reports. You will
be informed when notebook pages will be collected before the
report is due.
FORMAL LAB REPORT - Title and Author(s)
State the title of the experiment, your name, the date and your
laboratory section number, if applicable. Also state the name of
your lab partner(s). This information should be at the top of the
first page.
FORMAL LAB REPORT – Introduction
The Introduction states the purpose of the study and introduces
the reader with new ideas and topics. It also provides any
background necessary to acquaint the reader with the problem
being addressed, as well as providing the reader with references
to previous relevant work.
Although a portion of a formal report, it is sometimes easier to
view this section as a short essay, one in which the writer
describes the importance of his work, and the possible
application of his work to other areas of interest to the reader.
As in an essay, the Introduction begins with a broad description
of the principles being discussed in the report, and funnels
down, becoming more specific along the way, to a statement of
the specific objective of the study. It should acquaint the reader
with the main topics and ideas discussed in the experiment, and
should include definitions of key terms that are new.
In your Introduction, you will need to choose the relevant facts
from your textbook, lab manual or other materials available to

4. you, organize them in your own words, and present them in a
logical order that highlights and supports the proposed
experiment. Definitions of significant terms should be
included. In general, your introduction should be two to three
paragraphs long, concluding with the statement(s) of purpose.
FORMAL LAB REPORT - Experimental Information
Here you must give a concise description of what occurred in
lab with sufficient detail to allow the reader to repeat the study.
However unlike the audience for a laboratory text book, the
audience for a formal report does not need to be told to wash
the beakers or to insure there are no air bubbles in the buret
tips. It is essential, therefore, that the writer be careful not to
insult the intelligence of the audience when writing the
Experimental section.
Another difference between formal Experimental sections and
laboratory text books is that laboratory texts are generally
written in second person past tense, i.e., “Open the lab drawer
and take out your notebook.” Formal Experimental sections, on
the other hand, are written in the third person, past tense, i.e.,
“The KHP solution was titrated with NaOH until a slight pink
color permeated the solution.”
Preparing for this, it may help to summarize the procedure into
a bulleted list of about five main procedural steps and then to
convert the list to complete sentences. Be sure to mention any
significant deviations from the procedure as stated in the lab
manual.
In this section you should state significant information:
amounts of starting materials and products, reagents used and
their concentrations, instruments used, including their make and
model, and significant observations of chemical reactions. Give
a synopsis of what went on.

5. In general, remember that the audience would like to know what
was done, not what to do. In a report you must write in
complete sentences. Write in the third person past tense. One
final note, be forewarned that step-by-step cookbook
instructions are unacceptable in formal lab reports.
FORMAL LAB REPORT – Data and Calculations
The first step in completing this section is to use your data and
generate any tables or graphs necessary for the analysis. This
should be done in your lab notebook. Data may be graphed or
tabulated. Whether the results are graphed or tabulated will
depend on the data and the conclusions you draw. You need to
use your judgment.
Then examine your data and select the appropriate, pertinent
items for your formal report. Not everything in the data tables
in your notebook will necessarily go into tables in your report.
In your notebook you might have recorded initial and final buret
readings, but in your report you would only state the volume of
titrant used, i.e., the difference between the initial and final
buret volumes. Once the reliability of your data has been
assessed, you may tabulate your results. Having achieved this,
you can discuss and interpret your results.
Conclusions you draw from your data must be presented in a
clear, concise manner. Tables and figures (graphs are
considered figures) should be integrated into your text, as you
would find them in your textbook or in a journal article. You
should introduce data tables and figures with words using
complete sentences. Refer to figures and tables sequentially as
they are introduced. Figures and tables should be identified
with a separate series of number.
FORMAL LAB REPORT - Results and Discussion

6. This section is the meat of a formal report as it is where you
demonstrate your understanding of the experiment and its
results. It is also the most difficult to write, should take the
most time, and is generally worth the most points in your score.
Begin this section with a statement of results. When you have
finished working up your data, look it over to decide what
conclusions may be drawn. State your results briefly, using the
past tense. Write something about each table or figure, keeping
in mind that they present the data but they do not state the
results. Do not simply offer the data as your results. Be sure to
introduce all your results in this section.
This section will also contain error analysis. Before one can
draw conclusions from data, one must assess the precision and
accuracy of the results. A result is only as good as the accuracy
to which it was measured. To evaluate your data you must
know how reliable it is. Acquiring data on a brand-new
instrument does not mean that there is no error in the data, nor
are computer calculated results error free.
There is always some error in your measurements. In the
discussion of each error, a discussion of its effect on the
experimental outcome/results should be included. Listed below
are some common sources of error, all of which should be
considered in assessing your data.
· Errors in measurement: It is easy to misread an instrument,
particularly when using an analog device with several scales
located on a single meter. Make sure you are reading the right
scale. Make sure you know what the units are when recording
data from an instrument. Other common measurement errors
might be misreading a buret, not zeroing a balance, or
incorrectly taring a balance. It is common to take 3-5 readings
and use the standard deviation of the readings to estimate the
uncertainty.

7. · Errors in Recording or Recopying: It occasionally occurs that
numbers are transposed or decimal points lost when entering
data in your notebook or copying them to a table. This type of
error is hard to catch unless the number is totally unreasonable
or well removed from an observed trend in the other
measurements. Examples might be a pH of 23 or a series of
repeated measurements where four out of five readings gave
values between 0.2 and 0.8, but the firth reading gave 3.9;
clearly there is a problem with the fifth measurement.
· Errors in Computation: Double check your calculations.
Don’t assume your answer is wrong if it did not agree with your
lab partner’s or the literature. Watch your units and unit
conversions! Make sure they are consistent. Once you have
completed your calculations, consider if the answer is
reasonable. Always evaluate your calculations, particularly
your units.
Once you have assessed the reliability of your data, you can
discuss and interpret your results. You should first consider
whether you accomplished what was proposed in the
introduction and if your results were successful. What are the
significant sources of error in the experiment? At least three
procedural errors should be identified. How might they be
minimized in the future?
Begin the “Results and Discussion” section with your
interpretation of the results, and then perhaps a comparison of
them with expected values. Always try to put a positive spin on
your results if possible. You must also discuss the reliability of
your data, how the reported uncertainty was determined and
what its primary source was.
Things may go wrong in lab. However, even if your results are
questionable, it is still possible to write a good lab report.

8. Begin by stating what should have happened, then discuss what
actually happened and why the experiment went wrong. Never
begin your discussion with what went wrong. It is important
that you demonstrate that you understand both what should have
happened and what might have gone wrong. Note also that
there is a big difference between a null result and a failure to
get results.
FORMAL LAB REPORT - Conclusion
The purpose of the Conclusion section is to summarize the
pertinent concepts discussed in the R&D section. Always begin
your Conclusion by clearly stating your results and the
“goodness” or significance of your results, and relating them to
ideas presented in the introduction. In other words, if the
objective of the study was to determine the percent calcium
carbonate in an unknown sample, you should restate the
percentage, with its uncertainty, in this Conclusion section.
Important observations may go in this section as well. Discuss
the significance of the results. When possible, compare your
results with literature values. Discuss significant errors and
suggest improvements to the procedure or possible ideas for
additional experiments that could further support your
conclusion.
Then make a concluding statement(s) and relate your conclusion
to the ideas presented in the introduction. Note: Stating that
“overall the experiment went well” or that “I learned how to use
a piece of equipment” are not strong conclusions.
The conclusion is not to be a lengthy discourse. One paragraph
(about four to seven sentences) is the amount to be presented in
conclusion.
FORMAL LAB REPORT – References

9. Always cite any literature and websites used in preparing your
lab report. “Verbal Communications” may also be cited as
such. The specific format used to cite references varies from
journal to journal. You should always reference the lab manual.
You may have others if you cite literature values or refer to
your textbook for clarification of ideas.
Generally, all citations include the author’s last name and first
initial, an abbreviated form of the journal title, the volume
number, the first page number of the article and the year
published. In citing a scientific paper, the title need not be
given. In citing a book, begin with the author’s name, followed
by the title of the book, the publisher, where published and the
specific edition.
Examples
N. E. Triggs, M. Zahedi, J. W. Nibler, P. A. DeBarber and J.
J. Valentini, J. Chem. Phys., 96, 1822 (1992).
J. A. Halstead, N. Triggs, A. L. Chu, and R. Reeves in Gas
Phase Chemiluminescence and Chem-ionization, A. Fontijn
(ed.), p. 307-334, North-Holland, (1985).
FORMAL LAB REPORT - Formatting Guidelines for lab reports
Clarity and Style
Observe the rules of good grammar, spelling, and punctuation.
It is expected you will write in complete sentences. Proofread
your report before you turn it in. There is no bigger turn off
when grading a report than to find sloppy grammar and
incorrect spelling. It sets the tone “expect the worst” and it will
surely be reflected in your grade.
Reports must be typed and the use of a word-processor is
encouraged. Use 1-inch margins, 12-point font for text and 1.5-

10. line spacing. Choose a font that is easy to read.
Equations
Equations are presented as part of the sentence structure of the
text and are numbered for future reference. All symbols are
defined where first used. In formal reports, the first time an
equation is presented, it is identified by a number. Each use of
that equation is then referenced by that number, whether in the
section introduced or in later sections. Sample calculations and
results in any section may refer to equations previously
introduced, or new equations may be presented. Equations are
not grouped together, but are presented only when needed
during the course of discussion.
A very useful tool for inserting equations into your documents
is the equation editor available in many word processor
packages.
"The molarity of HCl was calculated from Equation 1, where M
and V are molarity and volume (mL) respectively. The mean
molarity of HCl for the three trials was 0.0985 M, and the
standard deviation, calculated with Equation 2, was ± 0.0002
M."
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Figures
One figure that is often used in Chemistry is a graph. The type
of graph you compose will depend on your data. Chemists most
commonly use an x-y scatter plot with the dependent variable on
the y-axis and the independent variable on the x-axis. All axes
should be labeled – the reader does not necessarily know what
you are plotting. And be sure to include the units for each axis,
for example, “time (secs)” or “Fe3+ concentration
(moles/liter)”. (You will be penalized if you leave axes labels
out.) Pay attention to your axes’ scales and make sure your data
fills the graph. The same data can look very different
depending on how it is scaled. Always consider whether it is

12. important to show that your data passes through the origin, or if
it s more important that your data fills the scale.
Generally on an x-y scatter plot, you do not connect the dots,
but simply draw the best straight line or curve through the data.
If you plot more than one set of data on the same axis, you must
include a legend to identify each series. Error bars are also
important and helpful in judging the significance of the data.
Usually these are only included for the dependent variable.
Figures (graphs) should be at least one-half of a page in size
and regression statistics also included if calculated. They need
to be numbered sequentially and include a relevant title. Ex:
Figure 1. Density of Metal, Volume (mL) vs. Mass (g)
Tables
Tables are used when graphs are inappropriate and the data
cannot be introduced in a single sentence of text. Each table
should have a title at the top and a table number by which it can
be cited in the text. Arrange your data by column rather than by
row. It is much easier to read down than across. Do not include
a column containing all the same numbers. Footnotes are
frequently used to convey specifics about a subset of data
within the table. Uncertainties in results should be presented
with the data in the table. Tables are sequentially numbered,
independent of Figures.
Abbreviations
Well-known abbreviations, such as mL, M.W., etc., may be used
without explanation. Otherwise, spell out the words the first
time they are used, followed by the abbreviation in parenthesis,
and use the abbreviation thereafter:

13. “Potassium hydrogen phthalate (KHP) was used as the primary
standard.”
Subtopic: Symbols
Many quantities have accepted symbols, i.e., pressure (P) or
temperature (T). It is often convenient or efficient to define
symbols for calculated or measured values.
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Click here for example Formal Report
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Rough Grading Rubrics for
Formal Report: Avogadro’s Law
Typed formal report: 30 points
1. Title: 2 points
Name, Partner’s name, title and date of experiment, lab section
should be included. Deduct 0.5 pt for each missing.
2. Introduction: 5 points
State the problem: What is the problem this experiment and/or
study try to solve? (1 pts) A short paragraph or a few
sentences leading to the background information.
Background: define important terms and how they are used to
solve the problem proposed (3 pts)
Assume you were in an age when Avogadro’s Law was just
proposed. Discuss the importance of Avogadro’s Law and how
to use it and other gas laws (Boyle’s Law and Charles’ Law) to
derive Ideal Gas Law. Students may also use other relevant
concepts.
Ends with a statement of purpose: what does the student want to
achieve through this experiment and how to achieve it? (1 pts)
A short paragraph of purposes. Students should provide some

14. insights, not in great details though, the methodology used to
achieve these purposes.
3. Experimental
Students should summarize narratively their revised procedure
here. No bullet point or numbered steps. No point value is
assigned. But deduct 3 pts if this section is missing and deduct
1 point if this section is not written in appropriate format.
4. Data & Calculations:6 points
Proper data table(s) to summarize all data and calculated result
(4 pts)
Proper data table should be included for all data and their
calculated result. All table(s) should be labeled with proper
table number and title. Be aware that students may use a
different table and may include different amount of data in their
table. However, all the major data and calculated result should
be included in the table.
Introduction to data table(s) (2 pts)
All data tables should be introduced and major data should be
described in words how they were achieved. Equations may be
used in this section to aid this purpose.
5. Results & Discussion: 10 points
This is the meat (or bread and butter ) of the formal report!
Result statements: 4 pts
Student should briefly summarize their results on both (1)
Verification of Avogadro’s Law; and (2) Calculated gas
constant R, including the percent error of R. 2 point for each
part.
Error analysis: 6 pts
Students should briefly assess the results, especially how linear
the excel graph is and how high (or low) the % error of R is.
Then students should identify at least three reasons or sources
of errors to account for the difference between their result to
literature value of R. These errors may focus on different part
of the lab or all of them. Students should also discuss how these
errors may have affected the experimental R value and how they
might have been avoided or minimized. 2 pts for each

15. reasonable error and corresponding discussion.
6. Conclusion: 4 points
Restatement of purpose, summarize calculated results,
significance of experiment. 1 to 2 short paragraphs are
expected.
7. References: 1 points
Student should include the lab manual and textbook from which
they get definitions of major concepts. Sources of the literature
values for Gas Constant R and vapor pressure of water should
be included as well. Students may have other references if they
used other resources to help them propose procedure or help
them interpret data and write formal report.
8. Overall Style of formal report: 2 points
3rd person, past tense, formatting, complete sentences, being
typed, well written, etc.
Determination of Purity Using Titration
INTRODUCTION
A common problem in chemistry is determining whether or not
a substance is impure and to what extent it is impure. Chemicals
used in experiments or for commercial purposes often need to
be pure to ensure safety and efficiency during reactions, but
determining whether or not a given substance is pure can be
difficult. If the chemical is an acid or a base, titration with a
standardized solution can be used to assess its purity.
In a generic titration, “one solution of known concentration is
used to determine the concentration of another solution through
a monitored reaction.”1 An acid-base titration works on the
principle that the acidic solution will combine the basic solution
to neutralize, altering the pH of the solution.
H3O+(aq) + OH- (aq) 2H2O(l) (1)
Eq. 1 shows that when equal moles of the H3O+ion and the OH-
ion are present, the solution is completely neutralized. 2 When
this dynamic equilibrium occurs in a titration, it is called the

16. equivalence point, and at that point a given reaction has a
characteristic pH. Thus, indicators, substances that can change
color depending on the pH, are valuable tools for monitoring the
progress of titration reactions. A few drops of indicator are
added to one of the solutions and the other solution is added
dropwise. When the moles of acid and base are equivalent, the
equivalence point is reached and adding one more drop of the
titrant will cause the indicator to change color, signaling the
end point of the reaction. The end point occurs just after the
equivalence point, but the extra titrant required to reach the end
point is negligible in calculations.
The titration method is useful in determining purity only if a
standardized solution, one with a known molarity, is available
for the titration. If a known volume of standardized solution is
used in a titration, then the moles of both acid and base can be
determined. From the moles, the mass of the pure substance can
be determined and compared to the mass of the impure
substance to find the percent purity.
In this experiment, a sodium hydroxide, NaOH, solution was
standardized by titration with pure hyrdrochloric acid, HCl.
HCl (aq) + NaOH (aq) H20 (l) + NaCl (aq) (2)
This reaction was monitored using phenolphthalein indicator,
which changes from clear to pink near a pH of 8, corresponding
to the pH at the reaction’s equivalence point. Once the molarity
of the standard NaOH solution was known, the solution was
used to titrate an impure sample of industrial grade muriatic
acid, HCl, again using phenolphthalein indicator, and the purity
of the muriatic acid sample was determined.EXPERIMENTAL
25 mL of pure 1.000 + 0.003 M HCl was measured using a
25.00 mL graduated pipet and added to a 250 mL flask along
with 2 drops of phenolphthalein indicator. Next, an NaOH
solution of approximately .1 M was created by diluting 75 mL
of 1 M NaOH to 750 mL with DI water. The NaOH solution was
then placed in a 50 mL buret and added dropwise to the HCl
solution until the indicator in the solution turned pink. The
above procedure was repeated three times to standardize the

17. NaOH solution, at which point three samples of approximately
35 mL impure muriatic acid were prepared and titrated again
using the NaOH solution and phenolphthalein.DATA
The results obtained from the above procedure may be found in
Data Tables 1, 2, and 3. In Table 1, the moles of HCl were
obtained from the measured volumes and then equated to moles
of NaOH. The molarity of the NaOH solution was calculated by
dividing the moles of NaOH by the volume of liters of NaOH
delivered during titration.
Moles HCl = Moles NaOH=Molarity x Liters HCl
(3)
Molarity, NaOH = Moles Solute/ Liter
Solution
(4)
Table 1: Standardization of NaOH