Chromatography of M&M’sCHM 1210L Lab report instructions for General Chemistry a
Why a Journal article report (JAR)? A primary goal of this course is to see
if you can think
like a scientist, interpret data, and communicate that knowledge to your
peers. Journal
article reports allow you to develop your understanding of the experiment and the
critical
thinking necessary for clear, concise communication of those ideas. This is also
a chance to
improve good writing, communication, and computing skills.
These instructions are meant to be general instructions for JAR type reports.
Specific
supplemental instructions may be given for some experiments.
Academic Honesty
Academic honesty is absolutely, unquestionably expected. Academic dishonesty, notably
plagiarism of lab reports, copying of pre-labs, and cheating on quizzes or
tests will result in a zero
grade for the work and could lead to failing the course. Please be aware that this
includes
copying lab partners’ files, tables, and figures. All students must each submit
original,
independent data analyses and lab reports. Do not work with anyone on your
reports except
The GTA’s, Dr. Sanders, or the university workshops. You will also be reported
to the WSU Office of
Community Standards and Student Conduct. For a more detailed description of
what is meant by
“academic dishonesty” please see the student handbook available at
http://www.wright.edu/students/handbook/. For a complete copy of the Academic
integrity policy
and the Code of Student Conduct, please refer to the following WSU Web pages:
http://www.wright.edu/students/judicial/integrity.html and
http://www.wright.edu/students/judicial/conduct.html, respectively.
Retaking the lab:
If you are retaking the lab you must reference yourself if any part
of your report is from
a previous submission to avoid Academic Integrity Violation. After the title
and names,
state that parts of the report were submitted previously and the semester when
it was
submitted. Keep in mind that we can check this.
“In-text citations”. After each statement that either quotes or paraphrases an
idea or
statement from another source there must be an in-text citation and corresponding
reference
at the end of the report. You may use either the MLA or the American
Chemical Society (ACS)1
method of citation and reference. In-text citations are usually of the form
of superscripts,
(number) or author – date: “The measurement of the ∆Hrxn was conducted using
the standard
calorimetry procedure presented in the lab manual.”2 or “…manual (1).” , or
“…manual (Grossie and
a Sum 2015.
Adapted by Lary Sanders from Dave Dolson summer 2013 and spring 2011
Underwood, 2014).” all
of which refer the reader to the reference at the end of the report in
this
case the lab manual.
Resources for writing lab reports are available here and through Pilot:
1. The outline below is a convenient reference for the main points for each section
2. The following description details the expectations for each section.
3. “Writing Laboratory Reports” Chapter 7 3 This is available through Course Electronic
Reserves. The instructions for using the reserves are on pilot as is
the reference for this
book should you need to reference in your report. In particular it
compares good and poor
ways of doing things. The whole book is available in Dunbar Library.
4. “How to write a lab report” Reed College. The link is on pilot.
In particular compare the
example of “well-written lab report” and “poorly written lab report” to see how yours might
be improved.
5. Do NOT get assistance from other students including your partner.
6. Get assistance from the University Writing Center, http://www.wright.edu/universitycollege/academic-
help/writing-center/overview,
031 University Library, 937-775-4186
(see link for hours).
7. Get assistance from the TA’s
Outline of sections of a lab report (provided for quick reference)
1. Title with claim. (meaningful but not the same as manual), author date, lab
partner, TA and
section.
2. Purpose: hypothesis to be tested, or Claim. We are substituting this
for the abstract as a
way to focus on the primary scientific objective.
a. This section replaces the abstract suggested in “Guidelines…”
b. State the purpose of this work?
i. Is it to test a scientific hypothesis such as verifying gas laws in
the upcoming
gas behavior lab or is to answer a scientific question such as, what
is the
vitamin C content in a particular sample?
c. Another way to look for the purpose is to identify the scientific
hypothesis to be
tested or the claim that the report is making
d. The purpose or hypotheses is the main point of the introduction. The claim
or result
is the main point of the discussion/conclusion section
3. Introduction
a. State the objective
b. Background theory – will include relevant citations
c. Methods: state briefly the methods by which the objective will be pursued
i. Are you using a titrimetric method, spectroscopic method, etc.?
ii. For what purpose will you employ these methods?
iii. Leave the details for the Experimental section
d. Finish with Purpose, hypothesis, point or “Thesis” .
4. Experimental method.
a. In General Chemistry, always begin with an in-text citation reference to
the
experimental procedures in the laboratory textbook or handout. ACS allows a
superscript number outside the punctuation if referring to the whole sentence.1
Also italic (1). Inside punctuation, or author year method such as (Grossie and
Underwood, 2014). Use the same number if a reference is repeated.b
b. Reference 1 in the “References” section should resemble the following but with
the
appropriate lab cited:
i. Grossie, D. A. and Underwood, K. A. , Laboratory Guide for Chemistry,
7th ed.,
“Analysis of Hydrated Copper Sulfate”, Wright State University, Dayton,
2014, Exp’t 5, pp. 25-28.
c. A brief statement of experimental method so that the reader need not have a
copy of
the text to know the general methods used. There should be enough information
that the reader can understand the experiment.
d. Details of any changes (omissions/additions)
e. “Materials used” (p xx) not so important for CHM 1210L or 1220L reports.
5. Data and Results
a. Primarily narrative text, supported with tables, graphs, figures as is appropriate to
each experiment
b. Organize presentation in logical order
For example, wt. % composition of Cu, sulfate, water before empirical
formula
determination
c. Report “Significant Outcomes” – present the relevant results, those used to
address
the purpose of the experiment.
d. Omit small details. e.g., mass of filter paper
e. Tables, Graphs, Figures presented within the report in an appropriate order.
f. Properly labeled (see p.xx)
g. Tables numbered and titled above
h. Graphs & Figures numbered below with caption
i. Presented with narrative text for the reader. Table and Figures “don’t exist” if
they
are not discussed in the text. Don’t assume the reader will find her/his way.
j. “Sample calculations” if required are put in an appendix rather than in
results. It is
assumed the reader knows how to do the calculations.
6. Discussion and Conclusion.
a. Most important.
b. Interpret/Explain results
c. Do results answer your question or support your hypothesis (was experiment
purpose satisfied)? Do the results support your claim? If not that’s ok but
you need
to explain why.
d. How strong is your evidence – what are the limits of your knowledge or
measurements?
i. Compare your experimental measurements to literature (known or
accepted) values when available
b In Word this can
be done with insert> cross-reference.
ii. Address sources and magnitudes of errors or
uncertainties in measurements
– random vs. systematic
iii. Is the direction & magnitude of possible errors in agreement with your
results compared to literature values?
7. References
a. State literature references
i. For references to theory
ii. For experimental method
iii. For literature values compared to your results
iv. Any other sources of information.
Detailed descriptions of Laboratory Report sections.c
Purpose
This is not normally a separate part of a journal article. We are
using it here in place of an abstract
to help you isolate main ideas of the experiment. What is the hypothesis
to be tested? Frankly –
why do the experiment and why should anyone care? In other words, what
scientific questions are
we attempting to answer? What claim will the report make?
Avoid starting with “The purpose is……”
Introduction:
The lab text tells you that this “should be a concise statement of the
theory/reason behind the
experiment, . . . “ Please don’t interpret “concise statement” to mean a
single sentence. This section
should introduce the experiment to your reader, generally in a paragraph or
two, but some
experiments may require more. Your introduction for the reader should explain important
concepts and introduce equations that will be used to evaluate the data
that will be presented later.
Variables in equations should be defined. The audience for this
section, as for the entire report,
should be for your peers – other students who have not yet performed this
experiment. Don’t
assume that the reader has more advanced knowledge so that you omit information
that should be
conveyed to a peer reader.
Notice the topics that make up the introduction section in the lab text. In
some cases additional
reading in other sources may be necessary for a more complete treatment of
background
information and concepts pertaining to particular experiments. Usually the
concepts and equations
developed in this section should be conveyed to your readers also – but they
should be understood
by you, the writer, and then presented to your reader in your own way.
Don’t simply take
sentences from the lab text or other reference and write it as your own
work – that is plagiarism.
And don’t simply read through the lab text introduction or other reference and
rewrite the
sentences in a slightly different way – this also is plagiarism. Write
from your own understanding
of the topics, which requires that you do some reading in the lab text and
perhaps read in other
resources and that you have an understanding from which you can write an
introduction of this
c Spring 2014.
Adapted from David Dolson CHM 127.
experiment for a peer reader. The writing in this
section and throughout the report should be
grammatically correct.
Take the “Heat of Reaction and Solution” experiment in the lab text as an
example. Based upon the
written introduction presented in the laboratory text, it would seem reasonable to
include the
following items in your laboratory report introduction section:
• Statement(s) that this experiment concerns calorimetric measurements to determine the
heat of reaction for several acid-base reactions and for a solution
reaction.
• Further statements of which reactions were studied
• Concepts of endothermic and exothermic processes, heat and heat capacity
should be
explained and that because heat is transferred between the reaction and the
calorimeter,
qrxn = -qcal. The heat calculated from the calorimeter’s point of view is of
the same
magnitude as that produced by or taken in by the reaction but has
opposite sign.
• Equations for calorimeter heat (qcal = C ΔT or qcal = mc ΔT) and to
define reaction enthalpy
change (ΔH = qrxn/moles of reactant) should be developed with an explanation
of the
symbols provided for your reader.
• Equations should be numbered for easy reference in the text.
Experimental Methods:
The American Chemical Society (ACS) Style Guide indicates when using a standard
method, as we do in most
of our labs, to “cite the appropriate literature and give only the details
needed”Error! Bookmark not defined..
For nonstandard procedures enough information needs to be given to replicate the
work.
Can the reader understand what was done without having the manual at hand?
The laboratory text should be referenced as the source for the experimental
procedures unless a
handout is involved. A simple reference citation is insufficient information
in a laboratory report,
which might well be read without the simultaneous availability of the cited reference
for procedure.
Accordingly, your report should present a concise description of the experiment even
though it may
omit many small details of the work.
Deviations of actual experimental procedures from the method described in the
laboratory text
must be stated.
Data & Results:
Here a full analysis of the results is presented. First show the raw data
and the equations used to analyze the
data. This is objective date without interpretation. Sample calculations, if required,
would be presented in an
appendix. The results should flow logically through the data from beginning to
end.
What goes in the results and what in the discussion? The results are
statements of fact and the
evidence to support that those facts. The evidence shows the data was obtained
correctly within
the stated uncertainty. The discussion will include interpretation of those results.
The lab text calls for students to state all results and numerical calculations,
present graphs where
appropriate and to compare results to literature values with stated uncertainties where
possible.
We would remind students to remember that this is a written document that
must use written text
to explain the results to your reader. A data table cannot simply appear without a
written
explanation given for its contents. The table should be introduced and
presented with text. Too
often, student writers believe that because someone with knowledge of the experiment will grade
their report there is no need to describe the results – the grader will know how
they were obtained.
The report should be written for a reader from your peer group but one who may
not have had this
same laboratory experience. The report must describe the experiment, its results and
their
meaning for one who has not performed it.
If there is a table it should have a title and labeled headings, and
measurement units must be stated
in some manner. All measurements have uncertainties associated with them, and these
should be
stated in some manner. An example, from the CHM 1210 Paper Chromatography
experiment, might
appear as follows:
Table 1. Chromatogram Measurements for Determination of Retention Factorsa
Amino Acid Solvent Distance Spot Distance Rf
b
1 = arginine 71 ± 1 mm 17 ± 1 mm 0.24 ± 0.01
2 = glycine 71 ± 1 mm 21 ± 1 mm 0.30 ± 0.01
3 = alanine 71 ± 1 mm 29 ± 1 mm 0.41 ± 0.02
4 = leucine 71 ± 1 mm 54 ± 1 mm 0.76 ± 0.02
5 = Cystine 71 ± 1 mm 11 ± 1 mm 0.15 ± 0.01
6 = Unknown# . 71 ± 1 mm 55 ± 1 mm 0.77 ±
0.02
7 = Unknown# . 71 ± 1 mm 22.5 ± 1 mm
0.32 ± 0.01
a. Adapted from reference 2.
b. An example uncertainty calculation appears at the end of this document for the
leucine
measurements – this actual footnote is specifically supplied for this document.
Footnotes are
not necessary for all tables.
Note that the table is “self contained”. It has its own footnotes (b)
explaining the calculation. It also
has a footnote (a) under the table indicating a reference in the text as in
“adapted from”. In MS
word these need to be done manually rather than try to use the “footnote”/”endnote”
tracking.
If there is a plot or graph, it should be computer created, it
should have a title, and the axes should
be labeled. Best-fit lines (or curves) through the data points should be fit using the
programs least
squares fitting algorithm such as Excel’s trendline function if the equation is
necessary for
calculating subsequent data. Understand that neatness does count
– if you wouldn’t want a
prospective employer seeing your lab report for a job interview don’t submit it
in this class without
improvements. Also note that figures have the caption listed underneath rather than on
top as is
Tables. Figures must be discussed in the text. Avoid captions the
equivalent of “x” vs “y” as in this
case “Fluorescence vs time” would tell the reader nothing that they can’t see in the
plot.
Figure 9. Time-resolved SO2(ν3) IR fluorescence emission observed through a
spectral bandpass
filter.4
Equations
Equations have a number after them so they can be discussed in the text.
This allows you to refer
back to the equation anywhere in the text. The first time mentioned,
variables should be defined
unless obvious.
For example we might say:
(Equation (5) vs. Eq. (5) is beginning of sentence versus within the
sentence).
“Equation (5) was used to determine the molality of the unknown solutions.”
Or “The molality of
the unknown solution was determed using Eq. (5)”.
∆Tf = iKfm (5)
where “i” is ……. (go on to define variables that are not obvious).
Discussion and Conclusion:
Often our experiments are done to illustrate a known
chemical principle. In this section the results
should be compared to the expectations arising from a theory or from earlier work
by other
scientists. Numerical data previously reported in the scientific literature
often serves as an
accepted or literature value with which your work may be compared. This
comparison must be
made within the expected uncertainty of your experimental value(s), and this
requires that you
consider the possible sources of error that may affect your reported experimental
value(s)
including the direction and magnitude of each effect. If, within twice the
expected uncertainty of a
measurement, your value is in agreement with a literature value you may make
this claim with 95%
confidence. (This statement arises from a consideration that for random errors 68%
of the
population is expected to fall within ±1 standard deviation and 95%
within ±2 standard
deviations.) If your observations agree with a chemical law that is to
be tested you may claim
experimental support for this law (for example the observation of a linear arrangement
of gas
pressure plotted against inverse volume supports Boyle’s law, as does a constant P⋅V
product for a
fixed mole quantity of gas). If the values do not agree within the
expected uncertainty of your
measurements or do not support an expected chemical law, it is necessary
to address the possible
reasons for the disagreement. Perhaps the magnitude of one of the errors is
larger than you may
have estimated or perhaps there may be the possibility of some specific
systematic error. The
method by which the measurement uncertainties were determined should be stated in the
text of
this section. And you should communicate support of or disagreement with
literature values or
chemical laws provided from your experiment with possible explanations given when
there is
disagreement. “Human error” is not an acceptable explanation.
If a literature value for a numerical measurement is not explicitly
stated in the lab text, it still may
be found in your lecture textbook or from another source. Ask the course
instructor or your GTA
and be sure to cite and reference the source.
References:
These will generally be the lab manual and the textbook. Some reports may
require additional
references to explain the theory or the discussion of the results. Normaly a
comparison with the
literature or expected result is necessary
We are accepting either the MLA or the ACS method of citing references.
A brief ACS method (Style
guide) is available on Pilot. If using Internet sources make sure they are
reliable. Wikipedia is not
an acceptable source as anyone can add content. However you may be able to find
reliable source
within the references of a Wikipedia article.
1 Brief ACS style guides are available on Pilot.
2 Grossie, D. A. and Underwood, K. A. , Laboratory Guide for Chemistry,
7th ed., Wright State
University, Dayton, 2014.
3 A short guide to writing about chemistry / Holly B. Davis, Julian F. Tyson, Jan
A. Pechenik
Boston : Longman, c2010 Ch 7; pp111-132
4 Adapted from Brumfield, B.R., M.S. Thesis WSU, 2005.