Y. Name 1
Formal Lab Report Requirements
Your lab report should be setup exactly as seen on the following pages:

Notice that there is a header inserted into each page with your first initial, last name, and
page number.

Use Arial font, size 11, and 1.5 line spacing

Each section of the lab report should have a title (bolded and underlined)
o
Abstract
o
Results
o
Background
o
Calculations & Post-Lab
o
Materials
o
Conclusion
o
Procedure
o
Works Cited
o
Data
General Lab Report Tips:
1) Check Spelling
2) Include units in every solved example calculation; units should be listed appropriately in each
data and results table (or graph).
3) Never use personal pronouns (I, we, us, our). This is a professional report and should be
treated as if it were going to be published in a scientific magazine (or online database).
4) Refer to procedural methods and things done during the lab in past tense. All of the action has
already occurred! Only use future or present tense if you are making a new prediction based
on your data or posing new questions to be answered during later research.
5) Neatness counts! Use rulers when hand drawing anything (especially when creating tables
and graphs), however, computer generate these tables/graphs whenever possible.
6) Do not copy word-for-word from the lab handout or any other source! This is plagiarism and
will result in a ZERO on this lab report and possible further consequences.
7) Your lab report should not match any other person’s! While data tables and calculations may
be the same between group members, NO written portion of your report should be the same
as anyone else’s!!!
Y. Name 2
Honors Chemistry
Mrs. Post – Mods X-Y
North Hunterdon High School
Your Name
Partner(s): Larry Laboratory, Tara Test-tube, Barbara Beaker, and Henry Hotplate
Title of Lab Experiment
Date Experiment was performed
Abstract:
An abstract is a paragraph (7+ sentences) that summarizes the completed experiment. In the
scientific world, the abstract gives enough information to the reader so that he/she can determine
what types of equipment and theories used during the experiment will be discussed in the report. You
should summarize, briefly, what was performed, and what the results were (think of it like the “spark
notes” version of your lab report) These are the four main components of an abstract, which should be
formed into an organized, well written paragraph:
1) Purpose/Motivation: What are you attempting to do in this lab?
Ex) The intended goal of this experiment was to produce and separate calcium carbonate
through a precipitation reaction. This precipitate was then massed and the percent yield was
determined.
2) Procedure/Methods: What scientific process did you actually do to get your results? Be brief
about your description. (you will explain it in more detail in a later section)
Ex) The lab involved the formation of a precipitate through a double replacement reaction of
two aqueous solutions. The precipitate was then separated via gravity filtration, rinsed, and
massed.
3) Results/Findings: After completing the experiment and analyzing the data, what were the
major results?
Ex) Upon the completion of three trials, the percent yield of calcium carbonate produced was
93.75%, 94.35%, and 95.62% respectively.
.
4) Conclusion/implications: What are the larger implications of your findings as they relate to your
purpose? (this is easier to write at the very end after writing the actual
conclusion)
.
Ex) The results of this experiment suggest that filtration is a fairly successful way to separate a
precipitate from solution. Furthermore, it is necessary to calculate the theoretical yield of a
product based on the stoichiometric quantity of the limiting reactant. This way, the actual yield
products can be directly compared for the determination of percent yield.
Y. Name 3
Background:
The background is between 2-3 full paragraphs (depending on the detail of underlying principles
used). Briefly develop the underlying principles or theory which is crucial to this experiment. Any
important equations or reactions utilized in this experiment should be included, labeled, and briefly
explained
in
this
section
of
the
report.
This
section
may
explain
why
a
certain
procedure/method/technique was utilized and how it will achieve the desired result. It may also
explain how an out-of-the-norm instrument works (like how a spectrophotometer reads wavelengths of
light to differentiate molarities based on absorbance). This section of the lab report must include at
least one reliable, academic OUTSIDE source of research BESIDES your textbook and/or the written
experiment. Any online/web sources that you use in your report must be printed out and
attached to the end of the report for your instructor to review. Also, the portions that you
paraphrased or quoted must be highlighted or underlined.
Ex)
In this experiment, a double replacement reaction between calcium nitrate [Ca(NO3)2] and
sodium carbonate [Na2CO3] was performed, resulting in the formation of the solid precipitate,
calcium carbonate [CaCO3] according to reaction 1 below:
Ca(NO3)2 (aq) + Na2CO3 (aq) CaCO3 (s) + 2 NaNO3 (aq)
Reaction 1
This type of reaction is commonly referred to as a “precipitation reaction”. A precipitate is formed
when a cation and anion, from aqueous solutions, ionically bond together and form a new,
insoluble compound known as a precipitate (“Precipitation”). The term insoluble means that a
substance cannot be dissolved in the given solvent, most typically water. While filtration can be
used for different reasons, this lab utilizes the method of gravity filtration in order to separate and
collect the solid precipitate produced for massing and analysis (“Filtration”). In the case of this
particular experiment, the precipitate was separated from an aqueous solution of sodium nitrate
[NaNO3] which was also produced as a byproduct of the reaction. Filtration can either be based
on differences in particle size or state of matter; here, the difference in state of matter between
the two products of Reaction 1 allows the separation of solution and precipitate.
Upon massing the precipitate, the percent yield can be determined according to equation 1
below:
Actual yield
Theoretical yield
x 100
Equation 1
The actual yield is the measured mass of the precipitate produced in the experiment. The
theoretical yield is the maximum calculated mass of the precipitate that could be produced given
the original starting quantities of each reactant. In order to determine this theoretical mass, the
limiting reactant must be determined and the stoichiometric molar ratio (using Reaction 1)
between the limiting reactant and precipitate must be applied to the calculation.
… this would continue on
Y. Name 4
Materials:
List all equipment, chemicals, or other materials used (in bullet form). If chemicals are used, they
should be listed by the chemical formula, name. If approximate masses used are known they should
be included. Solutions used with known molarities should always be included.
Ex)

1.0 M Ca(NO3)2, Calcium Nitrate

Glass stirring rod

1.0 M Na2CO3, Sodium Carbonate

Filter paper

Deionized water

Ring stand

Test tube

Iron ring

Test tube holder

Funnel

Test tube rack

Balance

Thin stem pipettes
Procedure:
Briefly describe, in a short paragraph, how the experiment was performed and what MAJOR
equipment was used. Do NOT give a step-by-step account of when to pour solution A into solution
B or “first, put on goggles. Next, place 2.5 grams of…”, etc. You are giving an overview of what
occurred so that another trained scientist could repeat your experiment with the same basic
principles in mind.
Ex) Solutions of 1.0 M calcium nitrate and 1.0 M sodium carbonate were prepared. Equal
volumes of each reactant were combined in an open test tube and stirred to ensure thorough
mixing. A solid white precipitate of calcium carbonate and an aqueous solution of sodium nitrate
were created as described by Reaction 1. A basic gravity filtration system was setup using a
funnel and ring stand. The contents of the test tube were then filtered and rinsed with deionized
water in order to ensure separation of the precipitate from the aqueous solution. Upon drying, the
mass of the precipitate was measured. Two more trials of the experiment were then preformed.
Data:
All data and measurements taken in the lab should be arranged into a data table and placed into this
section of the report. Often, you can set it up to match the data table given in your lab experiment.
Make sure that every table has a title and that every portion of the table is labeled with the
measurement and units. Whenever possible, make sure that the data table does not end up split
between two pages (even if this means that the data section must start on a separate page).
Y. Name 5
Ex)
Data and Measurements Table: Ca(NO3)2 and Na2CO3 Precipitation Reaction
Trial 1
Trial 2
Trial 3
Mass of Ca(NO3)2 (g)
2.32
2.10
2.25
Mass of Na2CO3 (g)
2.06
2.11
2.09
Mass of filter paper (g)
13.09
13.20
12.99
Mass of filter paper + precipitate (g)
15.41
14.37
14.30
Results:
Produce a results table that gives the final calculated answers for all the calculations that the lab asks
for performed during/after the lab. This table puts all the important calculations in one concise location
and it should be very organized. Make sure that every table has a title and that every portion of the
table is labeled with the measurement and units. Whenever possible, make sure that the table does
not end up split between two pages (even if this means that the results section must start on a
separate page). The results section should NOT include an ounce of calculations within it, only
final result values.
Ex)
Results Table: Ca(NO3)2 and Na2CO3 Precipitation Reaction
Trial 1
Trial 2
Trial 3
1
Actual mass of precipitate (g)
1.35
1.17
1.31
2
Theoretical mass of precipitate (g)
1.44
1.24
1.37
3
Percent yield (%)
93.75
94.35
95.62
Calculations & Post-Lab:
This section will NEATLY demonstrate the calculation work and set-ups including all the data numbers
used and appropriate units. You may type the calculations directly into the lab report, or, if you
choose, calculations may instead be hand written but they must be neatly written in INK, not
pencil! If anything is handwritten/drawn, use a clean sheet of computer paper and attach it directly
after the results section, then begin the post-lab section on a new page. Show ONE sample
calculation for each type of calculation that is necessary. For example, you would show work for how
each calculation was performed, but for ONE trial only (the assumption is that you did the calculations
for all trials exactly the same so one sample is enough to determine if it was calculated correctly or
not). Typically, the trial with the best results is the one chosen for showing sample work. In the
example above, trial 3 would be selected because the % yield is the highest. Be sure to include a title
addressing which trial is detailed in the sample calculations.
Y. Name 6
For any post-lab QUESTIONS which are not direct calculations, re-type and number the post-lab
questions and then answer them in complete sentences. If the post-lab requires any graphs they may
be inserted directly into this section or, if hand drawn (in ink) they are to be attached directly before
the conclusion section of the lab report.
Ex)
Sample Calculations: Trial 3
1) Actual Mass of Precipitate:
14.30 g – 12.99 g = 1.31 g CaCO3
2) Theoretical Mass of Precipitate:
LR
2.25 g Ca(NO3)2
ER
2.09 g Na2CO3
1 mol Ca(NO3)2
164 g Ca(NO3)2
1 mol Na2CO3
106 g Na2CO3
1 mol CaCO3
1 mol Ca(NO3)2
1 mol CaCO3
1 mol Na2CO3
100.1 g CaCO3 = 1.37 g
1 mol CaCO3
CaCO3
100.1 g CaCO3
1 mol CaCO3
=
1.97 g
CaCO3
3) Percent Yield:
1.31 g CaCO3 x 100 =
1.37 g CaCO3
95.62%
4) Explain why an insoluble compound does not dissolve in the presence of a particular
solvent.
An insoluble compound will not dissolve in the presence of a particular solvent because the
forces of attraction that form between the atoms of the compound (whether ionic or covalent)
are too great. This means that the attractive forces between the solvent and compound are not
strong enough to overcome the forces holding together the compound, thus it is insoluble in
that particular solvent.
Y. Name 7
Conclusion:
This should be 1-2 full paragraphs. A great deal of attention is focused on your ability to write a
sophisticated analysis of the lab. It should be a unified summary of your work on the topic under
study. It should not be brief, fragmentary, expansive, or excessively critical of apparatus or equipment.
Write the conclusion soon after completing it, and edit it a day or two later. The conclusion should
include the following:
1)
Success of lab based on accuracy and precision of results:
Compare the results to class averages (if known), evaluate percent error or percent yield
values. This is the section for commenting on the SUCCESS of achieving the designated
purpose/goal of this experiment based on the data/results evidence. You should include numbers
from the results section to support this evaluation
Ex) Upon completing three trials of this experiment, the average percent yield of the
precipitate, calcium carbonate, was 94.57%. All three trials were fairly precise, with less than a
2% difference in the percent yield between them. Additionally, in comparison to the theoretical
yields, the actual quantities of precipitate recovered during the experiment are all within one
tenth (0.1) of a gram for every trial. This analysis supports the fact that this experiment was
very successful: the results were both accurate and precise.
2)
Errors and Explanation:
Every lab has got them, what were they? How did they impact your results? Be specific… don’t
say, “Not heating the solid long enough caused a great deal of error” instead say, “By not heating
the solid long enough, some of the mass accounted for did not chemically decompose. This, in
turn, results in less oxygen gas being produced, increasing the percent error.
Ex) One significant error in this experiment was that some of the aqueous sodium nitrate
produced was most likely stuck inside the calcium carbonate precipitate. Although the sample
was rinsed with distilled water, it is very likely that the massed precipitate was not 100%
calcium carbonate. Additionally, another error found was that, when massed, the precipitate
was not fully dry. This means that the mass of the precipitate was inflated, not only due to
impurity, but also due to the weight of the non-evaporated water. Both of these errors suggest
that the true percent yield for each trial is most likely lower than the calculated percentages
due to the fact that the sample was impure and not fully dried. Finally, in Trial 1, some of the
precipitate produced was stuck to the stirring rod and was therefore not included in the mass.
This would mean that the true percent yield of trial 1 should be higher than what is reflected.
3)
How to Improve:
What could be done to increase the accuracy and the precision (assume that you have as much
time (and possibly money!) as you need to accomplish this. Include any part of this lab that did
not work out well and be sure to give an alternative that may work better. Could you try a different
method? Different equipment? A better chemical reaction? Different masses? etc…
Ex) While this lab was very successful, there are a few changes which could help to improve
both the quantity of calcium carbonate recovered as well as its purity. For example, when
massing the filter paper and precipitate, it would be beneficial to dry the sample in a chemical
oven to make sure no water is left behind to increase the measured mass. Also, instead of
using gravity filtration, it may help to separate the precipitate and solution if suction filtration is
used. This would require access to a vacuum but it would increase the speed at which the
filtration occurs. Finally, increasing the number of times that the precipitate is rinsed clean with
distilled water will help reduce the amount of sodium nitrate trapped within the calcium
carbonate. This will significantly improve the purity of the precipitate.
Y. Name 8
Work Cited:
Include all outside SCHOLARLY references you used in the lab report including your text book (if you
used it for reference anywhere in the lab report …FYI: your textbook does not count as your
required outside source). This should be written the way your English teachers have shown you,
according to MLA format. The website http://owl.english.purdue.edu/owl/resource/747/01/ may be
useful if you have questions about MLA. Additionally, the media specialists would be able to help you
find appropriate references and/or write works cited.
Ex)
"Precipitation Reactions." University of Memphis. Department of Chemistry, n.d. Web. 13 Feb. 2014.
<http://www.chem.memphis.edu/bridson/FundChem/T17a1100.htm>
“Filtration.” University of Arizona. Department of Chemistry. n.d. Web. 16 Feb. 2014.
http://quiz2.chem.arizona.edu/vip/filtration/