Chemistry Lab Report-Titration of a Diprotic Acid Lab Report
Number of pages: 2 pages/double spaced (550 words)
Number of source/references: 1
Order instructions:
General Advice:
• Never, ever use the term “Human error”, doing so will result in a 0 for the section in which the
phase is found, and continued use of the phrase over the course of the term will result in 0pts
given for entire reports which contain the phrase.
• Avoid pronouns (I, me, we, us, she, he, they, them, etc)
• Abbreviate complex or long compound names/concepts to streamline the narrative
o The first appearance of such an abbreviation should be the full name followed by the
shortened form in parenthesis (ie, “The acid used was Hydrochloric acid(HCl)…. The
powder was then dispersed into the water, and 25mL of HCl added after the solution
had cleared.”)
• Equations, both chemical and mathematical, should be separated from the rest of the text and
indexed for reference later; ie
“A very common reaction used to introduce the concept of single replacement reactions, spectator
ions/net ionic equations, and acid/base neutralization involves Hydrochloric Acid (HCl) and Sodium
Hydroxide (NaOH), and can be written as follows:
HClaq + NaOHaq NaClaq +H2Ol (1)
The state labels of HCl and NaOH clearly indicate that both Na+ and Clions
are spectators in the process,
so reaction 1 can be written as a net ionic equation in the following form:
H
+
aq + OHaq
– H2Ol (2)
While water is produced in neutralizations plainly seen in reaction2, the non-water product made up of
the spectator ions [in this case], is what defines the term “salt”; hence any non-water product of an acid
base neutralization is considered a salt.”
• It is considered taboo to actually call attention to the formal title of report aspects; avoid the
use of phrases like “The purpose of this experiment is…”, “My hypothesis is…”, “In conclusion…”,
“In reference to the hypothesis…”, “…was a source of systematic error…”, “…was a source of
random error…”, etc. It is your job in writing a report to outline these concepts and make each
clear in the context of the report, and in so doing there is no need to blatantly call out the
concepts and disturb the flow of the reader. This may seem counter intuitive, but avoiding those
phrases forces you, as a writer, to expand and elaborate on details you could easily overlook
otherwise. Not allowing yourself think though your writing will inhibit your ability to reach and
present a depth of understanding otherwise achievable. For instance; Rather than making a
bland, vague statement like,
“A random source of error was spilled sugar.”
It would be better to use observations and logical association to FRAME the error and its source
by saying,
“Sugar spilled during preparation of the standard solution could have skewed the correlation curve;
the mass lost did not contribute to the total mass of the solution used to determine density, but was
accounted for in making the correlation. Such an oversight, if consistent, would lead to determination
of concentration for the unknown solution to be higher than would have been expected for the given
density, which is in agreement with the bias observed, though the effect on each data point cannot be
fully quantified or accounted for after the fact.”
The latter statement displays a depth of understanding and thought (even though the mass lost
is probably insignificant in terms of calculation; more on that later) completely absent from that
of the superficial former statement. Note here that it isn’t the number of words or sentences
which improved the passage, but the depth of insight. Consider the following,
“During preparation of the solutions, sugar was spilled due to a lack of precision and imperfect
technique. Instead of going into the flask, the sugar was lost all over the counter top and scale. This
likely was a random error which gave a false result. Spilling sugar should be avoided in the future by
being more careful to avoid this error, because it will greatly increase the accuracy. Better lab
practices will help tremendously to improve the result of future repetitions of this experiment and
avoid the unnecessary loss of sugar.”
This last passage has the same number of words as the well-written statement, but gives no
critical assessment. It uses unnecessary adjectives, pointless repetition, and broad
generalizations to mask its lack of substance; avoid writing like this [and, in general, any similar
style of communication] at all costs. Even using the first example statement is preferable to this
latest passage because it wastes less time and attention and gives the same amount of prudent
information (still aim for the second example if you can manage it).
Lab Format:
Abstract:
• The abstract should be a brief answer of the “Why?”, “How?”, and “What?” of the experiment,
in that order; remember the questions discussed at the beginning of every lab session.
o state the goal of the experiment (Why)
o then a brief description of the method used (How)
▪ should include technique names and any specific compounds unique to the
procedure, no specific concentrations or equipment
o conclude by summarizing the results (What)
▪ Numerical values (the number YOU calculate)
• With uncertainty where appropriate
▪ Literature values (which ever set YOU used)
▪ Absolute error (the magnitude of the difference between your value and the
literature)
▪ Relative error (%error)
▪ Report all error and lit for each calculated value; or an average if you calculate
multiple values for the same chemical concept
Introduction:
• Used to frame the historical and/or contextual relevance of the experiment
• Should be three paragraphs long, or contain three subsections
o First; Context
▪ Broad/real world/big picture relevance
• What is this used for, how and why?
▪ Chemical background (theories and equations)
▪ Hypothesis
o Second; Procedure
▪ Method with enough detail to reproduce the experiment
▪ NOT a step-by-step summery of the procedure (though that’s often a helpful
starting point, it’s important to identify the key steps and factors)
▪ Do not include information obtained during data collection
▪ Do not include general glassware (eg flasks, burettes, watch-glasses, beakers)
• Do include equipment if that specific piece of equipment was not
interchangeable and was paramount to the outcome of the experiment
o Third; Wrap-up
▪ How will does the procedure connect to the background theory; what
information will be obtained and how can you use it to achieve the goal?
▪ Note some possible short-comings, or difficulties which could be expected
(easier since you have already completed the experiment)
▪ Conclude with how the procedure connects to your hypothesis
• Do not do that by “This relates to my hypothesis because…”
• While the introduction is written in past tense, it should not hint at, or out-right discuss the
results of your experiment
Data:
• Limit the information presented to the sets that you will reference in your report
• Use logical divisions, spacing, and groupings when organizing your data
o Use titles and captions; eg Figure 1: graph of titration data, Table 1: qualitative data
gathered by the class over the course of the experiment
o Never let a single data table break between pages
▪ Sub-divide data and split one table into multiple tables if it doesn’t fit in the
space you set aside
• This section is for “raw” data, hence anything that requires calculation or analysis to conclude
should be saved for the “results” section
o One exception can be titration curves; if a graph is collected as raw data, then it can be
included in this section, whether you reformat it or not.
o All other graphs/figures that you make will likely be expected in the results section
• The section should be concluded with a short paragraph summarizing observations made during
data collection, initial impressions of the process, or any anomalies/hardships encountered
Results:
• Present any numerical results obtained through analysis in cohesive tables
o Your calculated values
▪ And the values and constants used for your calculations (either in the table or
discussed in the caption for the table)
o The literature values
o Margins of error
▪ Absolute difference and bias
▪ Relative (%)
▪ Uncertainty if applicable (if you take an average, it should also come with a
standard deviation [+/- X units])
o Tables and figures labeled and captioned appropriately
▪ Title
▪ Number (index)
▪ Caption describing context of information
▪ Appropriate size and format for the information displayed
• Sample calculations
o One of each type of calculation you preformed, ie
▪ Density
▪ Molar conversion
▪ Unit conversion
▪ Dilution
▪ Mathematical transformation (ie, [H+
] to pH)
▪ Note; samples of averages, st.devs, %error, and other simple transforms are not
necessary unless the form used was specialized for some specific purpose
o Should show every relevant step in algebra
o Must be typed; no snap shots or hand written equations (if you’re doing all of your
calculations by hand in this day-and-age, you’re wasting your time and leaving room to
mess up anyway; learning how to use spreadsheets will greatly reduce strain and time
spent in both initial calculations, troubleshooting, and projections)
▪ Leave space
▪ The format doesn’t matter so long as I can follow the math; insert eq in word,
LaTex, excel parenthetical syntax, or other script software display, it doesn’t
matter
o Keep calculations in proximity to the results section
• This section should be concluded by a short paragraph evaluating the observed results of your
experiment, as well as the reliability and accuracy of each test if possible. (Where your results
trustworthy? How can you tell? Where there any trends among the number/test? What do they
say about the experiment?)
Discussion:
• Three paragraphs (just like the intro)
o Interpretation of results
▪ Restate the numerical results, deviation from lit. vals, and relative error
▪ What is shown by the result (what is implied by the outcome)
▪ Why is that what the test indicates? (relate to theory)
o Error analysis (*The MOST important paragraph of the report for this class*)
▪ Identify the source of error (there will always be error to discuss, and multiple
sources)
▪ Describe how it affected your result (see general advice section for example)
▪ Identify the level of relevance and direction of Bias
• As an example, many students end up citing the balance as a source of
error, but consider the following: most lab-samples for this class will be
~1 g and that the uncertainty of the balance is usually +/- 0.0005g which
is a 0.05% margin of error… so does the precision of the balance
account for a 10% difference in values?
• If you were to cite a loss of mass, you must be clear what the affect
would be on your value (whether the loss will decrease or increase the
calculated value [you might have to do some math with hypothetical
values to figure it out]) and if that effect matches the bias that was
observed (was your value higher or lower than it should have been?); if
the error you propose would make the value larger, but your result was
smaller than it was supposed to be, then that error is likely not
responsible for the deviation of the experimental result
▪ Explain how the errors can be avoided or accounted for in the future (be
specific)
• Recognizing the types of error (for you to recognize, don’t write about
an error as being a “random error” or “systematic error”)
o Random – unavoidable consequence of uncertainty,
characterized by incoherent distribution of deviation; can only
be minimized by repetition, or incorporation of more precise
techniques
o Systematic – consequence of a flaw in experimental procedure
or equipment, characterized by consistency in deviation; can
easily be corrected by adjusting correlation, recalibration of
equipment, or altering experimental parameters
o Wrap-up
▪ Make sure you answered all post lab questions (found in the lab manual [D2L])
• Further questions are meant to be answered as a part of the coherent
narrative of the Discussion section, not as a separate entity; no bullet
points, no awkwardly inserting question and answer in the middle or at
the end without context: Think about how the questions apply to the
experiment, frame them, and give a logical answer.
• Further questions can also be worked into the error analysis where
applicable
▪ Reiterate the purpose of the experiment
▪ Explain the connection between purpose and the observed result
▪ Was the experiment a success, a failure, or inconclusive in respect to your
hypothesis (and don’t say, “this experiment was successful…”, etc)
Remember, there is such a thing as spending too much time on reports; walk into a wall enough times
and you’ll eventually get through it, BUT it’s easier and much faster to find a door. Alone, time spent
does NOT equal good grades; if you’re stuck or consistently spending too much time on reports, use the
tutor room, schedule meetings with me or your teacher, or ask your classmates (NO plagiarizing), but
get help and input on how to improve your time management and analysis/writing skills. And also
remember that different TA’s focus on different aspects of grading and writing, and you will need to
adjust accordingly. The silver lining is that there is a HUGE number of buffer points (for this 1 credit
class) if you simply show up to class prepared and do what you’re supposed to do, so a bad report grade
or two won’t sink your overall grade or your GPA.
Let’s try to make this Term as painless as possible, no one wants to have to stress about Gen.Chem
classes.
Statement of Understanding:
By signing the statement below, it is hereby acknowledged that responsibility for reviewing the
requirements and expectations (this document, the lab handout, the rubric, and the guidelines in the
manual) for each assignment falls solely on the signer.
The use of any of the following faux pas may result in an assigned grade of 0 points, until the assignment
is corrected and resubmitted (within a limit of 3 days of grading, after which the grade will stand):
• Use of the pronouns I, me, we, us, they, them
• Any mention of the “TA(s)” or “students”
• Use of the term “human error” in any context
• Failure to include section titles
• Failure to separate mathematical or chemical equations from the rest of the text
• Reference to error being “random error” or “systematic error”
The resubmitted assignment will be evaluated for the corrected material pertaining to the previous
transgression(s); any additional changes made to the content, explanations, or analysis of the original
document will not be reevaluated.
The signer may seek clarification on any, and all, feedback or requirements pertaining to all work
assigned in this teaching laboratory class over the course of the academic term. However, there will be
no retroactive alteration of the score assigned to an assignment as a result of a failure to obtain
clarification prior to the submission of said assignment. Additionally, it is the responsibility of the signer
to initiate contact in seeking clarifications if necessary.
I, __________________________, have read and understand the expectations for formal lab reports as
required by James Lohman, the TA for this lab course, ______________________.
Signature:_________________________ Date:______________________
