Cuyamaca CollegeSpring 2022
CHEMISTRY 141 AND CHEMISTRY 142
GENERAL CHEMISTRY I & II
LABORATORY NOTEBOOK AND LAB REPORT GUIDELINES
Dr. Robert Dutnall
Keeping a lab notebook is an essential skill that all scientists must develop, and it will be a
major focus in lab this semester. The organizational, recording and presentation skills required are
also applicable in careers outside of science. The laboratory notebook is as important as the actual
experiments you perform and constitutes a permanent record of your experimentation. Proper
documentation of scientific work makes it possible for researchers to submit papers for publication,
apply for grants or patents, or simply archive results which may become significant at a later date. If
the experiments turn out to be successful (not only in results, but perhaps also in monetary value),
then the lab notebook serves as evidence of discovery admissible in court should ever a controversy
over ownership arise.
In this course you will be keeping a hand-written record of your experiments in a lab
notebook. In some experiments you will also use computer graphing programs to prepare and print
high quality graphs to convey experimental results. You will also use your lab notebook to prepare
lab reports to communicate the purpose, procedures, data and conclusions of your experiments.
The laboratory notebook constitutes a permanent record of your experimentation. Therefore,
ALL entries are to be made in non-erasable INK and mistakes are to be crossed out with a single
line (for example, errror: do not use white out, do not scribble out illegibly). Make sure to record all
relevant information. All work should be done in your approved laboratory notebook and not on
separate sheets of loose paper. Data and observation entries must be made directly in the notebook
at the time and location that they occur (not written on another piece of paper and copied later, not
remembered and then written in later). The only exception to this rule is data that is recorded and
produced as a print out from a scientific instrument or computer program. These printouts must be
securely taped into your notebook in an appropriate position and labeled and dated.
Keep your notebook well organized and leave room for additions or corrections that may
occur. Clearly tell the reader where to find things (based on page number) if you need to insert
corrected information elsewhere. Each experiment should always be started on a new page of the
notebook. Also start the Data and Observations section on a new page. Before you leave lab, you
must have the Data and Observation section in your notebook initialed. The original lab notebook
section for each experiment is to be photocopied and turned in as part of your lab report (detailed
instructions below). Data is not to be rewritten.
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Key Elements in a Good Lab Notebook
It must be complete and up to date. Every detail of your laboratory procedures, results, analysis
and conclusions must be recorded so that any individual could repeat the work as you did it.
It must be honest. The details must be recorded immediately after carrying out the procedure, as
you first carry out the analysis of the data and as you make observations. Mistakes must be
recorded and explained. Bad data must be included along with the good and included in the
analysis and conclusions.
It must be readable. Most records are read at one time or another by other individuals. Your
notebook may never be neat, but your handwriting and your general organization must be good
enough so that other people can interpret exactly what you did.
Every activity associated with lab must be dated by writing the date (month/day/year) at the
top right of each page. Activities include mental, as well as physical time spent on the project.
In addition to sections describing the purpose, procedures, data and observations, examples of
activities include ideas proposed to modify or improve the procedures, design of a follow-up
experiment, as well as all thoughts pertaining to the analysis or interpretation of the results.
Organization of the Lab Notebook
The lab notebook will be organized in the following order:
1. Exterior Title (Cover)
Your name, course title and number, section number and semester should go on the cover.
2. Title Page
Your name, course title and number, section number, the name of the school, the semester and the
name of your lab instructor. Also include either your address, phone or email address or other
information that could allow your notebook to be returned in case it is misplaced.
**Number and date the front of each page in the upper right hand corner from this point on.
3. Table of Contents
Two pages should be set aside as a table of contents to list expt number, expt title, page number.
This is useful for quickly finding specific topics in the notebook and must be kept up to date.
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4. Instructions for each of the experiments
Only write on the right hand page of your open notebook. This leaves room for additions or
corrections or scratch work or other annotations to be made on the left page. Each experiment should
be organized as follows and in this order:
The first page of a new experiment should include the date, experiment name and number. The
experiment name or number and date of work completed should then be repeated at the top of each
page relating to that experiment.
** IMPORTANT NOTE**
The next two sections (Purpose and Procedure) must be completed in your lab notebook by the
start of the lab period in which the experiment is to be done, or it will be assumed you are not
prepared to do the lab and you will be asked to leave the lab.
Two to four sentences in essay style introducing and explaining the purpose or objective of the
experiment(s) to be performed. Be sure to include the experimental technique(s) to be used during
the experiment and any determination of unknowns, if applicable. This section should be written in
your own words. Copying from the lab manual is plagiarism. Use the present passive tense (no
personal pronouns) and the occasional future tense when required.
A detailed summary of each step in the experiment. The procedure is typically presented as a
numbered, step-by-step set of directions for performing the experiment. Do not use personal
pronouns. Write steps in the imperative tense. Indicate all chemicals used along with the amount of
each used. Also include any safety information important to the experiment. Use clearly drawn
diagrams if useful. A labeled, annotated picture of the experimental set up is never a bad idea,
especially if it is complex or unfamiliar to you (and can help if you need to set it up again). Do not
copy the procedure verbatim. This section should also be written in your own words. Long steps can
be broken up into a series of shorter steps. Writing “Refer to Step 5 on p. 36 of the lab manual” is
unacceptable. The important thing to remember here is that you should theoretically be able to use
the instructions in your procedure rather than the lab manual to perform the experiment. Any change
to the experiment on the day of the lab should be noted here as well, along with the name of your lab
partner if you work in pairs. Sometimes I may direct you to change the procedure, or sometimes you
may decide to change a step(s) based on experience because of the observed outcome of a previous
step (following consultation with me). So leave a small amount of space between each step to allow
you to add more information or to direct to where to find the additional information.
Page 3 of 7
Data & Observations
A legible and complete record of all observations and data collected during the course of the lab
period in which the experiment is performed. These notes will lead you to accept or abandon a
hypothesis and help you decide the course of future experiments. You must be as objective and
honest in recording your observations as you are in making them. Most of the observations and data
section can be a narrative description, a story telling what you did and what you saw. Use the first
person to make it clear that you did the work. If someone else did the work, be sure that point is
obvious. If you work in pairs, be sure to note that as well. Write in reasonably brief, declarative
sentences as the work progresses. The instructor will initial this section when you have completed
your lab work for the day.
Start this section on a new page. Recordings, observations and notes about the experiment
should be taken as the experiment occurs and in non-erasable ink. These are to be taken directly
in order to ensure accurate transcription of what occurs during the experiment. Writing data and/or
observations later is subject to poor recollection and the possibility of fabricating results. When
writing data, be sure to include the proper units and the proper number of significant figures. In
general, students often fail to record observations or make assumptions about what is obvious. Some
experimental procedures in the lab manual will have explicit directions or sometimes hints as to
what observations should be made. However, these may not be the ONLY possible observations;
there could be more. Take time to note the color, appearance, heat lost/gained, nature of precipitates,
approximate time of certain steps, etc. Remember that descriptions of starting materials are
important as well. Think of the observations as a guide for someone who will be doing the
experiment after you (or for you if you wanted to repeat the experiment). What kind of “road
markers” can you leave that will let them know they are performing the experiment correctly and
that it is progressing as expected?
As this section is being written as the experiment occurs I expect it to be a little rough and to
contain errors with appropriate corrections. Any errors should be corrected by a single strike-through
the errror and then writing the corrected word or value. Make sure it is clear what you are recording
so that you (and anyone else reading your report) know what it means later. Use titles or markers to
state what a recording is. For example: “Mass of empty 50 mL beaker: 452.386 g”. Not just
“452.386 g”. If you make any adjustments to the procedure make note of them and describe if
necessary (for example you may use more or less of some material, you may use a different piece of
equipment, you may decide to add or skip a step).
You can improve the organization of the data/observations if you:
1) organize the data in separate areas, using headings/subheadings if helpful that could be based on
major steps or substeps in the procedures,
2) leave space between separate areas of data so that you can add notes or comments or make
corrections without significantly changing the flow of this section (it’s awkward to have to refer to
another page or jump back and forward to find things),
3) think ahead about what data you will be collect based on the procedures. If you collect multiple
trials or several different measurements for a single item it might be better to create a table that you
can complete as you complete these steps. You can also add a summary table at a later date to help
“reorganize” your data for more convenient access.
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In general, think about how to organize and present your data and observations so that you
can quickly and easily find the information you need for calculations and analysis. Remember you
can also only analyze what is recorded! If the data is not there you cannot use it. Taken together the
procedures and data/observations should be sufficiently detailed so that someone with a reasonable
training in chemistry and with access to similar materials and equipment could repeat your
experiment and get the same results within experimental error.
If, when you finish your Data & Observations section for a given lab, there is a blank space on the
notebook page, line through the space diagonally to cover the entire blank and write the date and
your initials above the line.
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A lab report is required for each experiment performed. Lab reports must be typed or written in ink
in a legible, organized fashion. Each lab report will be organized in the following way unless the
instructor gives other directions:
1. Title Page
2. Purpose, Procedure, Data & Observations
4. Computer Printout and/or Graphs (if applicable)
About each section:
Title Page: This section should contain experiment title, name, and chemistry course number
Next, the following three sections should be photocopied (or scanned and then printed) from
your lab notebook. Be sure to copy the entire page including dates and page numbers for credit:
Data & Observations
Analysis: This section is NOT to be done in your notebook but on a separate, clean sheet of
paper (front side only). It is the final draft of your answered questions and calculations, and should
be done in pen or typed. Questions that require written answers must be given in complete sentences.
This section contains your calculations used to obtain results, if applicable, and answers to all
questions posed in the experiment’s post-lab questions. Make clear which questions you are
answering. Rewrite the question as a subheading before your answer and leave appropriate space(s)
between answers to clearly delineate them. The analysis section should be organized and presented
so that someone reading your report can follow your reasoning. Heading and subheadings can be
used to help organize and present the results.
Before presenting a calculation, explain what you are calculating, what equation you are
using, and why. Always begin the calculation by presenting just the equation before ﬁlling in values
and solving for the unknown variable in subsequent steps. If there are multiple trials, you just need
to show detailed calculations for one trial, unless told otherwise. The results of the all the trials can
then be reported in an organized table after the sample calculation. Finally, if required, statistical
analysis (e.g. mean, standard deviation) and any graphs created from raw data are also included in
this section. Note that graphs should be properly annotated with a numbered title, axis legends etc.
Graphs can be printed on a separate page and referred to from the text of the analysis section (e.g.
“see Graph 1: Density of water at different temperatures”) and placed in order at the end of the
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Computer Printouts, if applicable. (We’ll discuss this in class when it applies)
Conclusion: A minimum of three paragraphs in which your results are presented and discussed.
Think about what the purpose and/or objectives of the experiment were as you address in the
following order: (1) What you learned from the experiment should be discussed, (2) What were the
results of the experiment? DO NOT JUST REPEAT ALL YOUR DATA but give
values/information of importance related to the purpose of the experiment. What was the identity of
an unknown, what was the numerical value of some parameter that was a goal of the experiment?
What was the error associated with this value (or other statistical parameters), etc. For example,
“The value of the gas constant was determined to be 0.08215 L.atm/mol.K (average of two
independent trials), a 0.11 % error compared to the accepted value of 0.08206 L.atm/mol.K.”, (3)
Sources of systematic experimental error in the experiment – at least three – should be discussed in
the third paragraph, along with their possible implications and effects in the experiment. Do NOT
discuss safety issues here. This discussion of error should be done in some detail for credit. You
must cite specific, concrete examples of possible errors and how they will affect the results of your
lab (percent yield, empirical formula, percent composition, determination of an unknown, etc.). Also
include any questions here that you may have come up with as a result of your experimental work
(Note: a full conclusion may not always be required. Instructions will be provided).
Grading of Lab Reports
Unless otherwise stated the lab report must be turned in at the beginning of the lab period a week
after completion of the experiment to receive credit. Labs turned in late will not be accepted. Some
experiments are done in pairs. Be sure to include the name of your partner in your lab notebook in
the Data and Observations section. Questions and calculations are to be done independently even
though the experiment itself may have been done in pairs. If identical work is found on two lab
reports for an experiment, both students will receive no credit for the reports.
The majority of your lab reports will be graded in great detail for some or all of the required
sections. Other lab reports will be graded for completeness and organization. In general, lab reports
will receive a total score out of 100 based on scores in the following categories: title
page/organization & clarity, prelab questions (if applicable), purpose & procedures, data &
observations, analysis, conclusion, lab etiquette (your behavior in lab). The number of points in each
category will vary with each lab report but will always total 100 points.
Presentation and attention to detail always count, so make sure that everything is in the right order
and that you write clearly and legibly. Everything should be well-organized and well-written. Pay
attention to your spelling, punctuation, and grammar! Do not expect poorly-written lab reports to
receive full credit. Is it time consuming? Yes. If you barely spend time on the lab report, it will be
readily apparent when compared to your peers. Focus on quality and allow enough time to write an
excellent lab report!
Page 7 of 7
Graph of Temperature vs Time for Dissolution of Magnesium Sulfate (Run 1)
Temperature (Deg. C)
Graph of Temperature vs Time for Dissolution of Magnesium Sulfate (Run 2)
Temperature (Deg. C)
Graph of Temperature vs Time for Dissolution of Magnesium Sulfate (Run 3)
Temperature (Deg. C)
Graph of Temperature vs Time for Dissolution of Magnesium Sulfate (Run 4)
Temperature (Deg. C)
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