Chemistry: CHM 1025C
Laboratory Manual
Fall 2009 Term
Written,
modified, and/or adapted by
Professor John Taylor, Dr. Joseph Langat,
and Dr. Kathleen Laurenzo
Reviewed,
Edited and/or Revised by
Dr. Marcelle Bessman, Dr.
Stephen Lukacs, Dr. Vandon White,
Dr. Terry Waggoner, Dr. Paula Thompson,
Professor Barbi Baker,
Professor Peter Mullen, and Professor Rhoda Yost
Some Content
Originally Supplied by:
Dr. Andrea Wallace, CGCC and
Dr. David Summers, USAF
Academy
Florida State College at Jacksonville
North Campus
Jacksonville, Florida
Fall 2009 CHM 1025C Tentative Laboratory
Schedule
Week
1. Welcome/Laboratory Notebook
Lab
Safety Film Notes
Lab
Safety Rules and Safety Contract
Laboratory Diagram
Laboratory Equipment
NFPA and
HMIS Safety Codes
2. The Scientific Method/Controlled Experiment:
Analysis of the “Andromeda Strain”
Movie
3. Introduction to Measurement/Metric
System
Bean
Jar Experiment
Gasoline Project
4. Density (and Specific Heat Option)
5. Graphing Data
6. Atomic Spectra/Dot Structures/Nomenclature
7. Chemical and Physical Properties
8. Cation Analysis
9. Anion Analysis and/or Case of the Six White
Powers
10. Analysis
of a Hydrate
11. Video “Who
Killed the Electric Car”
12. Alka
Seltzer Analysis
13. Acid/Base
Titration
14. Molecular
Mass of a Gas via Vapor Density
15. Organic Structures and Isomer Number Problems
16. Laboratory Practical
CHM 1025C
Laboratory Guidelines
As you know from your syllabus, your chemistry labs will
account for 20% or more of your final grade in this course. As such, it would be in your best interest to
complete your lab work in a timely and conscientious manner. The following is a set of guidelines which
will help you make the most of your lab grade:
1) Welcome
to college: coherent sentences required.
Points will be deducted for incorrect spelling, bad grammar, and other
miscellaneous abuse of the English language.
2) Watch
your values. Significant figure and
rounding errors will result in appropriate deductions, in both data and
calculations. If you are not sure how to
round a number or how many sig figs you should have, ASK.
3) Your
Lab Instructor/Assistant are not cryptographers. If we cannot read your handwriting, we will
assume that you have the wrong answer.
Do not cram data or answers in the margins of your lab manual; use a
separate sheet of paper and indicate the question number or label your data
appropriately. If we have to guess, we
will guess that you are incorrect.
4) Poor
results will result in significant deductions. Do your work carefully, paying close
attention to precision and accuracy,
and asking questions BEFORE a crisis occurs.
Always remember that doing the
lab slowly but correctly the first
time takes much less time than doing it wrong and having to do it over.
5) Late work will be penalized by at least
20 percent deduction per week unless
authorized by the instructor, so turn your work in on time for full
credit. This point deduction is subject
to increase at your instructor’s discretion.
Pre and post labs are due at the beginning
of the lab, not 5 minutes after lab starts.
Your work will be considered late if it is not submitted as you enter
the lab.
6) Values
without units mean absolutely nothing, so make sure to add the appropriate
units to all values unless they are provided for you on the report sheet.
7) Failing
to write your name on your lab means more guesswork for your lab
instructor/assistant…and an automatic 25%
penalty.
8) You are required INDIVIDUALLY to work each experiment
except when noted you may work with a partner. Copying results and/or
answers from anyone WILL NOT be tolerated.
Even if you and your partner work together on the post lab, if you can’t
find an original way to show your calculations or word your answers, chances
are you don’t understand it anyway. Any copying will result in a deduction of the
total points possible for all values and/or answers that were copied.
CHM 1025C
Welcome to the
Chemistry Lab D-204
Introduction
The experiments in
this lab manual have been chosen to introduce you to some basic and important
laboratory equipment and techniques. In
addition, some of the experiments provide an opportunity for you to test your
laboratory skills by analyzing “unknown” samples. Each experiment is designed to be completed
within a two-hour period. You should be
able to complete the work in the time allotted.
This time allotment does assume, however, that before coming to the
laboratory you have read the introduction to the experiment, have answered the
pre-laboratory problems (which introduce needed concepts), and have carefully
read the experimental procedure.
Laboratory Notebook and Reports
Student Must
purchase a Laboratory Research Notebook in the bookstore,
ISBN #r 9781930882508 for ~$12.50. All students must use this Notebook.
This notebook has 50 NCR duplicate pages. One page will remain in your notebook
as a permanent copy, the other is designed to be torn out and submitted to your
instructor. A lab report must be submitted for each experiment that you
perform.
For most experiments, the report will be in three
parts:
(1) the pre-lab due at the beginning of the lab
period,
(2) the data and observations collected while in the
lab, and
(3) the calculations and post-lab questions to be
completed after the procedure.
The majority of the labs in this manual have a data
recording and report sheet created for you to copy in your Laboratory Research Notebook
as part of your pre-Lab Activity. If no
report sheet is provided, you must create your own in your laboratory notebook.
All submitted recordings and reports must be neatly
handwritten, and should contain the following elements, when applicable, in the
order given:
Pre Lab (do NOT tear out your pre-Lab report from your
notebook unless directed to do so. Your instructor will initial your pre-lab
report during the beginning of lab):
1. Your name,
section number, and date.
2. The title of
the experiment and the date on which it is performed.
3. Answers to any pre-lab problems must be
written in your notebook (unless your instructor requests you to submit the
hard copy handout-filled out before the lab). Then the actual data recording
page must be neatly laid out in your notebook.
Data and Observations:
4. All data and observations are to be entered directly
into your notebook as you go through the experiment. Each student
must record his/her own data. Do not use
a sheet of paper and then transcribe the data into the notebook later. Do not record data in any datasheet you are
given. Neatness is important, but honesty and accuracy are equally as
important.
Numerical
data must be identified by a tag (e.g. “mass of Erlenmeyer flask – empty”)
and include units (g, mL, etc.). Use
the correct number of significant figures to report your data.
For example:
Mass of empty Erlenmeyer flask 52.650 g, not 52.65
Mass of flask + benzoic acid 53.000 g, not 53
Note
that you record both masses, not just the difference between the two. Similarly, for measurements with a buret, you
should record both the initial and final buret readings, not just the
difference between them. See the sample Data Recording Sheet provided with the
experiment. (You first two buret readings must be initialized by your instructor as
with many of your other first reading with measuring equipment.)
All data is to be entered in ink; no pencils and no
erasures. If an error is made in recording data, draw a
single line through the mistake, correct it nearby and initial the
correction. Do not obliterate any entry. If a substantial portion of a page is to be
discarded, cross the material out with an X.
Neatness and care in recording data and calculations
are a plus, but it is more important
that the notebook be an immediate and permanent record, “warts and all”, of
everything that happened in the lab.
Turn in your duplicates with your report.
NOTEBOOK ORGANIZATION
5.
Title Page:
List your name, address and phone number along with the course section and
instructor name. At the bottom, Copy the
Lab Safety Contract and sign it.
Table of Contents: fill in the list of experiments as you go into the cover which has the
Table of Contents. List the date, title
and beginning page number of each experiment.
You will turn this in at the end of the semester
Before coming to the lab,
read the experiment to be done and do the prelab exercises. In your notebook, write a title and the date
of the experiment, a brief statement of purpose. Make notes in your notebook and work out a
tentative procedure and data tables to be filled in. This is called “preparing your notebook to accept data” and will save you time as
well as organizing your thinking. It is
usually not possible to anticipate everything.
Make any corrections and additional observations as you work through the
lab.
Experiment #1 Safety Lab and Lab Orientation
a. On a page 2 of your lab
notebook you will begin the Safety Lab. At the top of the page place your name,
section number and the date. Then, place the title:
Safety Lab
b. Then place a subheading: ACS Safety Film Notes:
As you watch the film, record notes or emphasized statements which will become
a rough set of safety rules.
c. Make a rough sketch of the room in your notebook
on the next page. Label on the
sketch the following: Safety shower, emergency eyewash, safety blanket,
goggle/glasses cabinet, first aide kit, two major wash up sinks for hand
washing and hardware equipment drawers identified by the instructor.
d. On a new page (page 4 or later) as a post lab
report, list at least 20 or more lab safety rules from the three handouts and
the ACS film.
e. On the separate page
(page 5 or later) of your lab notebook Sketch the NFPA symbol and then copy a
more detailed or specific hazard for each NFPA numeric category from the Safety
Codes handout. Explain what each number represents in each category
f. In your lab notebook on
a separate page (Page 6 or later) sketch the HMIS Labeling System and list the
descriptions for each number for each category.
g. In your lab notebook (at
the bottom of page 6), state the purpose behind both system and why they are
different.
h. Using
Chemical Date Bases on the Internet, copy on a new page (Page 7 or later) in
your notebook the data sheet from the MSDS Assignment handout and fill in the
form for the chemical assigned and submit this page by the second lab period.
(Instructor’s note: Safety
Lab will be the longest report in this course as it requires a lot of copying
of information you may need during a lab and/or handling chemicals. Most
reports are usually only one, two or three pages in length depending on the
calculations.)
Final Report – Non
Formal:
6. If you have copied a printed report
sheet from this manual you have two copies in your research notebook. Include a
copy of this data and its summary in your final report. Also include your name, section number, and
date on every page.
7. Calculations: There should be a separate section devoted to
the calculations unless the data report sheet has left room for a simple
calculation, such as the Density Lab.
Otherwise, the calculations should be completely separate from your data
and results. You must show every
mathematical calculation that you perform.
8. Answers to any Post Lab questions
and/or conclusions belong on separate page in your notebook unless ample room
is obviously provided.
Final REPORTS – Formal:
Most
of labs include a datasheet that will serve as your non formal report. However
there will at least one lab, usually the last week, requiring a more formal
report. The following format should be
used.
A. Title: the name and number of the experiment, name of your
lab partner(s), if any, and the dates of the experiment and of the report.
B. Purpose or
Abstract: a statement describing the
major goals of the experiment.
C. Procedure: describe how you went about the experiment. Usually a reference to the handout will
suffice; however, you should mention any changes or deviation from the
procedure as given to you. Rewriting the
whole procedure is an unnecessary duplication of effort.
D. Data: record, in tabular format where possible, all
pertinent data collected, calculated values and results. It is often appropriate to have two tables,
one for original data and another for results.
E.
Calculations: show equations
and calculations used to arrive at final results. A general formula and one
example are sufficient for repetitive calculations. Include here any required graphs.
F.
Conclusions: discuss the results of the experiment and how
they relate to the concepts in the reading material. Was the stated purpose achieved? If not, why not? Include a discussion of major possible errors
and their impact on the experiment. The
conclusion section is the most important part of the report and has the most
influence on your grade. The prelab
mini-lecture will give you information about the important points of the
lab. Listen carefully and take notes.
G.
Post-lab:
Answer any questions or exercises included as part of the experiment.
9. Pre and Post Lab calculations are designed to be
performed individually, with the answers given to the correct number of
significant figures and with the correct units.
10. Pre and Post Lab questions are designed to be answered
individually. Answers should be concise,
legible, and in your own words (do not plagiarize or otherwise copy from
texts, websites, or your classmates).
Sample
Safety Contract – Lab Notebook Page 1
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Exp #:
One
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Experiment/Subject:
Laboratory Safety Contract
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Title Page
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Date:
/ /09
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Page 01
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Name:
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Lab Partner:
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Course:
CHM 1025C
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Section #
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Name: _________________________ Email: ____________________________
Address: _______________________ 2nd Email:
_________________________
_______________________________ Phone #: __________________________
__________________ Cell Phone: ________________________
Course: CHM 1025C
Section #: __________
Professor: _______________________
I,
____________________________, have watched the ACS Laboratory Safety Film. I have
read four different sets of Safety Rules from various colleges provided by my
instructor. I have synthesized from these rules and the safety film a list of
at least 20 rules written in this Laboratory Notebook which I agree to abide
during all formal laboratory activities and experiences in FCCJ North Campus’s
D-204 Chemistry Lab. I agree to wear proper safety glass at all times during
lab activity, regardless if I, myself, am not currently performing any
activity. I agree to lose points on my current lab if I am not wearing these
safety glasses. I understand that protective aprons and gloves are available at
my option to use during fomal lab activity. I have sketched in this laboratory
notebook, the layout of the North Campus Chemistry Lab D-204 and have noted the
placement of all safety features. Equipment and supplies in this Post Lab
Safety Report.
Signed:
_______________________Date:________________
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Signature:
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Date:
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Witness/TA:
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Date:
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Florida State College @ Jacksonville North Campus
Fall 2009 Chemistry Schedule
– FCCJ North Campus
–
The following are the scheduled CHM
1025C Courses at North campus. All six sections will be doing the same experiment
each week. If you are absent from a lab there is no makeup. However, with the
permission of your instructor and the other scheduled lab instructor, you may
on an emergency basis attend and complete that weeks lab at an alternate time.
CHM 1025C (23
sections-district-wide, 1 hybrid, [6@North] )
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CHM1025C - Introduction to General Chemistry
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4 Credits
|
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Additional Fee: $15
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Description: This course is an introduction to the concepts of inorganic
chemistry including structures of matter, atomic theory, nomenclature,
bonding, gases, solutions, equilibrium, and acids and bases. This course is
for students who have had no previous chemistry and plan to major in science,
engineering, pre-medicine or pharmacy.
Prerequisites: MAC 1105 or satisfactory score on placement test.
Corequisites: None.
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307804
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NORTH
CAMPUS
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D0207
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1:30PM
to 3:25PM
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MW
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8/31/2009
- 12/18/2009
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TAYLOR,
JOHN T
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NORTH
CAMPUS
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D0204
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11:15AM to 1:15PM
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8/31/2009
- 12/18/2009
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TAYLOR,
JOHN T
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307805
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NORTH
CAMPUS
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D0207
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5:00PM
to 7:05PM
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MW
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8/31/2009
- 12/18/2009
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TAYLOR,
JOHN T
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NORTH
CAMPUS
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D0204
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7:15PM to 9:15PM
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8/31/2009
- 12/18/2009
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TAYLOR,
JOHN T
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307812
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NORTH
CAMPUS
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D0210
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12:30PM
to 2:20PM
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8/31/2009
- 12/18/2009
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LANGAT,
JOSEPH K
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NORTH
CAMPUS
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D0204
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2:30PM
to 4:30PM
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8/31/2009
- 12/18/2009
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LANGAT,
JOSEPH K
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307815
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NORTH
CAMPUS
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D0207
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1:30PM
to 3:20PM
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8/31/2009
- 12/18/2009
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TAYLOR,
JOHN T
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NORTH
CAMPUS
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D0204
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11:15AM to 1:15PM
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8/31/2009
- 12/18/2009
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TAYLOR,
JOHN T
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309292
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NORTH
CAMPUS
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D0210
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5:00PM
to 7:00PM
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TR
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8/31/2009
- 12/18/2009
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LANGAT,
JOSEPH
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NORTH
CAMPUS
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D0204
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7:15PM to 9:15PM
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8/31/2009
- 12/18/2009
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LANGAT,
JOSEPH
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314616
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NORTH CAMPUS
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D0207
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7:15PM to 9:25PM
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MW
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8/31/2009 - 12/18/2009
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LANGAT, JOSEPH K
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NORTH CAMPUS
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D0204
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5:00PM to 7:00PM
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8/31/2009 - 12/18/2009
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LANGAT, JOSEPH K
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315049
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NORTH CAMPUS
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D0210
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11:00AM to 3:00PM
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8/31/2009 - 12/18/2009
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WHITE, VANDON E
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NORTH CAMPUS
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D0204
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9:00AM to 10:50AM
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8/31/2009 - 12/18/2009
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WHITE, VANDON E
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Chemistry Laboratory Equipment:
Laboratory Safety Rules
(main source: Dr. David Summers)
Laboratory
accidents can result in loss of time, damage to clothing and other property,
and personal injury. By following
suitable precautions, you can anticipate and prevent situations that could lead
to accidents.
You must make yourself completely familiar
with the following safety rules. You will be required to sign a
Laboratory Safety Contract stating that you have read these rules, agree to abide
by them, and have watched the ACS Safety Video.
At the beginning of the second laboratory period you may (instructor’s
option) take a short multiple-choice and/or true false quiz on the rules; if
you miss more than one question, you must pass a retest before you will be
permitted in the laboratory. In your lab notebook copy at least 20 safety rules from the
three handouts and the ACS video. Then copy the Laboratory Safety contract at
the bottom of the first page and sign it plus submit to your instructor the one
to be held on file at FCCJ’s Laboratory Supervisor’s office.
Rules
- Do not work in the lab unless the lab
assistant/supervisor or instructor is present. No unauthorized experimentation is
allowed.
- Work carefully with full awareness of what you
are doing, so as to avoid dropping or breaking equipment or spilling
chemicals. Keep reagents and
equipment well back from the edge of the lab bench. Never run in the lab.
- You may
provide your own pair of safety glasses/goggles and wear them in
the lab at all times or you may wear the eye protection glasses available
in the cabinet in the lab room D-204. Safety glasses MUST meet or exceed
ANSI Z87.1 (this should be indicated on the packaging). A lab apron or lab coat should also be
worn at all times while working in the lab.
- You must wear shoes without open
spaces; sandals and open-toe shoes are not acceptable.
- Confine long hair and neckties;
they may catch fire, get into chemicals, or get caught in apparatus. Loose jewelry or rings can also be a hazard. Frilly or flared clothing, especially
synthetics, are not safe around flames unless covered with a lab apron or
coat.
- Do not bring food or drink into
the lab. No eating or smoking is
permitted in the lab.
- Never taste a chemical.
Smell a chemical by fanning the air over the container to waft the
vapor to your nose; never smell directly.
Do not touch chemicals with your hands unless specifically directed
to do so; if contact occurs, immediately flush the area with cool water.
- Mercury vapor is invisible but
toxic over time. A broken
thermometer should be reported immediately
to the instructor.
- Never look directly into an open vessel in which
a reaction is occurring that could cause spattering. When heating materials in any container,
be sure that the open end does not point in the direction of other persons
or yourself.
- If any chemical gets into your eyes, flush with
water for at least 15 minutes.
- In case of fire, turn off the burner first. If there is a fire in a beaker, try to smother
it with a watch glass or wet paper towel placed over the beaker. For an open flame, use the fire
extinguisher pointed at the base of the flame. If the fire is uncontrollable, close all
windows and evacuate the room and pull the fire alarm located near the
emergency exit or in the hallway.
After evacuating to a safe place, call 911, and campus security @
766-6008 if you instructor is not present..
- Skin burns should immediately be placed under
cold running tap water for 5-10 minutes in order to remove the heat.
- If clothing catches on fire, use a fire blanket
or safety shower.
-
Do not force a glass tube or thermometer
into a stopper; the glass can break and gash or stab you. Instead, lubricate the end of the glass
with glycerin; hold both the glass and the stopper with a cloth towel to
protect your hands; grasp the glass close to the stopper; insert with a
slow twisting motion (see figure below).
- Report all accidents and injuries to the
instructor as soon as emergency action has been initiated.
- Never place chemicals directly on the balance
pan. Instead, use a beaker, flask,
watch glass, or piece of weighing paper.
- Read the label on a bottle twice before using the
contents. Never contaminate the
contents of a bottle by putting reagents back into it. Do NOT waste reagents; if you take too
much, share it with others who still need your chemical.
- Label any sample or mixture that you prepare.
- Never mix any reagents unless specifically
directed to do so.
- When mixing water and acid, always add acid to
water otherwise violent spattering may occur. Remember the word “acid” alphabetically
comes before “water,” so acid-into-water.
- Dispose of waste chemicals as directed. If a waste container becomes full, tell
the instructor or lab assistant so they can get an empty replacement. Don’t just ignore the situation.
- Do not use cracked glassware, as it may break
when stress is put on it. Place
broken glassware in specifically designated containers in order to prevent
injury to the cleaning personnel.
- If you discover that bottles of chemicals need to
be refilled, tell the instructor or lab assistant.
- Keep
the lab bench and tables clean.
Wipe up all spills. Acid
spills should be neutralized with sodium bicarbonate (which can be
obtained from your instructor or lab assistant).
Laboratory
Safety Rules-CGCC
1.
Wearing
approved safety goggles is required at all times while in the lab.
2.
Be
aware of what is going on around you.
3.
Unauthorized
experiments are prohibited.
4.
Follow
directions carefully.
5.
Food
and beverages are prohibited in the lab.
6.
Clothing
which protects is necessary.
7.
Locate
the fire extinguisher, eye wash, safety shower, and first aid kit.
8.
Know
how to operate all safety equipment.
9.
Never
pipet by mouth, taste chemicals, or directly smell chemicals.
10.
Avoid chemical contact with skin, eyes, and clothing.
11.
Read chemical labels thoroughly and observe all precautions.
12.
Never return chemicals to a reagent bottle unless told to do
so.
13.
Never pipet directly from a reagent bottle.
14.
Do not carry reagent bottles to your desk.
15.
Do not weigh chemicals directly on to the balance.
16.
Dispose of chemicals in proper containers, according to
directions from the instructor.
17.
Never point a test tube containing a reacting mixture towards
yourself or another person.
18.
When inserting or removing glass tubing, protect your hands
with a towel and gently twist, never force.
Use glycerin for lubrication if necessary.
19.
Keep a neat, uncluttered laboratory bench.
20.
Place broken glassware in the designated container.
21.
Report all accidents such as burns, cuts, chemical spills,
etc.
22.
A burn should be treated immediately by washing it with cold
water.
23.
Do not remove chemicals or equipment from the lab.
24.
Make sure gas and water are turned off before leaving the
lab.
25.
Always wash your hands before leaving the lab.
Obtain
Separate Set of Safety Rules from Old CHM 1015 Lab Manual of FSCJ old Handout
for the third set to review.
Obtain
Separate Set of Safety Rules Handout provide by North Campus
Obtain
Emergency Procedure lab Handout by North Campus
Safety Codes NFPA
Hazard
Codes
ChemAlert
rates hazards numerically inside the NFPA (National Fire Protection
Association) diamond. This symbol was
chosen for its universality.
The diamond has a red segment
(flammability), a blue segment (health, i.e.
toxicity), a yellow segment (reactivity), and a
white/blank segment (special warnings such as radioactivity or no water). Printed over each is a bold black number
expressing the degree of the hazard.
The
numerical ratings are:
4 = extreme hazard
3 = severe hazard
2 = moderate hazard
1 = slight
hazard
0 = according
to present data, none
Storage Codes
The storage code is assigned according
to the chemicals worst hazard:
RED Flammable
YELLOW Reactive and Oxidizing Agents. May react
violently with air,
water, or other
substances.
BLUE Health
Hazard. Toxic if inhaled, ingested, or
absorbed
through the skin.
WHITE Corrosive. May harm skin, eyes, or mucous membrane.
GREEN or Presents
no more than moderate hazard in any category.
ORANGE
On the separate page of your lab notebook
you should copy a more detailed or specific hazard for each NFPA category as
shown below:
Link to the following Government web site for more details:
http://www.sefsc.noaa.gov/HTMLdocs/nfpahazard.htm
This site has the following symbol
HEALTH - The degree of health hazard of a chemical or material
is based on the form or condition of the material, as well as its inherent
properties. The degree of health hazard
of a material should indicate the degree of personal protective equipment
required for working safety with the material.
1 is for slightly hazardous (toxic)
material which requires only minimal protection (for example, safety glasses
and gloves) in addition to normal work clothing to work with safely.
2 is for moderately toxic or a
hazardous or moderately toxic material which requires additional PPE or
equipment (e.g. chemical goggles, lab/work smock, local ventilation) in
addition to that required for less toxic material. Consult the MSDS for
specific health hazard and proper PPE to use with this material.
3 or 4 is for highly to extremely
toxic (deadly) materials (and any carcinogen, mutagen, or teratogen). These materials will require specialized
equipment (e.g. respirator or exhaust hood, full face shield, rubber apron,
specialized glove, handling tongs, etc) beyond that required for moderately
toxic material. You must consult the
MSDS and/or other safety information to determine the hazard (acute or chronic)
and the proper PPE and engineering controls to safely use this material.
FLAMMABILITY or FIRE HAZARD - The flammability or fire hazards
deal with the degree of susceptibility of the material to ignite and burn. The form or condition of the materials, as
well as their properties, affects the extent of the hazard. Many hazardous materials such as acetone and
gasoline, have a flash point (ignition temperature) far below freezing and will
readily ignite with a spark if the vapor concentration is sufficient.
1 is for materials with a flash point
above 200ºF.
2 is for materials with a flash point
below 200ºF but above 100ºF.
3 is for materials with a flash point
below 100ºF but above 73ºF.
4 is for materials with a flash point
below 73ºF.
REACTIVITY - The reactivity hazards deal with
the potential of a material or chemical to release energy. Some materials are capable of rapid energy release
without any catalyst, while others can undergo violent eruptive or explosive
reactions if they come in contact with water or other materials. Generally this rating is used to indicate the
potential to react if the material is heated, jarred, or shocked.
1 indicates a material that may be
reactive if heated and one that reacts with water.
2 indicates a material that may react
violently without detonation.
3 indicates a material that may
detonate or explode if subjected to a strong initiating force or heating under
confinement.
4 indicates
a material that readily detonates or explodes.
SPECIFIC
HAZARD
- An open space at the bottom of the NFPA diagram can be used to indicate
additional information about the chemical or material. This information may include the chemical or
material's radioactivity, proper fire extinguishing agent, skin hazard, its use
in pressurized containers, protective equipment required, or unusual reactivity
with water.
OX or OXY indicates a material that is
an oxidizer.
W or W
indicates a material that is water reactive.
ALK indicates a material that is
alkali.
COR indicates a material that is
corrosive.
RAD indicates a material that is
radioactive.
Special
Labeling Requirements
All containers that hold carcinogens,
reproductive hazards or acutely toxic chemicals must be properly labeled
concerning the health hazard posed by the chemical. Most containers will have the chemicals
hazard clearly displayed on the label.
However older chemicals and containers of solutions that are mixed in
the lab must be properly labeled by the laboratory worker. The laboratory worker may write the hazard
class (e.g. carcinogen, etc.) on the container or use labels available from
their Supervisor or Chemical Hygiene Officer.
Lab Symbols You Must
Know:
The MSDS web site may be accessed at the following:
http://www.ilpi.com/msds/ref/nfpa.html
Safety Codes: HMIS
In your lab notebook sketch the following HMIS
Labeling System and list the descriptions for each number:
Below is a paragraph about the two labeling systems:
“At first glance, the HMIS® and NFPA labeling
systems appear quite similar. Both have four sections colored blue, red, yellow
and white. HMIS® uses colored bars, while NFPA uses colored diamonds. HMIS®
attempts to convey full health warning information to all employees while NFPA
is meant primarily for fire fighters and other emergency responders.”
In your lab notebook, the purpose behind
the both system and why they are different.
MSDS Relevance
Specific sections of an HMIS® label
include the following:
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Health
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|
o
The Health section conveys the health hazards of
the material. In the latest version of HMIS®, the blue Health bar has two
spaces, one for an asterisk and one for a numeric hazard rating.
If present, the asterisk signifies a chronic health hazard,
meaning that long-term exposure to the material could cause a health problem
such as emphysema
or kidney damage.
NFPA lacks this important information because the NFPA system is meant only
for emergency or acute
(short-term) exposures.
According to NPCA, the numeric hazard assessment
procedure is different than that used by NFPA.
Here are the numeric rankings for the HMIS system:
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4
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Life-threatening, major or permanent damage may result
from single or repeated overexposures.
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3
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Major injury likely unless prompt action is taken and
medical treatment is given.
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2
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Temporary or minor injury may occur.
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1
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Irritation or minor reversible injury possible.
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0
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No significant risk to health.
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Reactivity (HMIS® I and II - now obsolete)
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|
o
The criteria
used to assign numeric values (0 = low hazard to 4 = high hazard) were identical to those
used by NFPA. In other words, in this category, the systems were
identical.
This
version is now obsolete. The yellow
section has been replaced with an orange section titled Physical Hazards
- see the next section for more information.
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Physical
Hazard (HMIS®
III)
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|
o
Reactivity hazard are assessed using the OSHA criterion of physical hazard.
Seven such hazard classes are recognized:
§
Water Reactives
§
Organic Peroxides
§
Explosives
§
Compressed gases
§
Pyrophoric materials.
§
Oxidizers
§
Unstable Reactives
This version replaces the now-obsolete yellow
section titled Reactivity - see the previous section for more
information. As with the Health and Flammability sections, the level of
hazard is indicated using numeric values (0 = low hazard to 4 = high hazard):
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4
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Materials that are readily capable of explosive water reaction,
detonation or explosive decomposition, polymerization, or
self-reaction at normal
temperature and pressure.
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3
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Materials that may form explosive mixtures with water and are
capable of detonation or explosive reaction in the presence of a strong
initiating source. Materials may polymerize, decompose,
self-react, or undergo other chemical change at normal temperature and pressure
with moderate risk of explosion.
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2
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Materials that are unstable and may undergo violent
chemical changes at normal
temperature and pressure with low risk for explosion. Materials
may react violently
with water or form peroxides
upon exposure to air.
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1
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Materials that are normally stable but can become unstable
(self-react) at high temperatures and pressures. Materials may react non-violently
with water or undergo hazardous
polymerization in the absence of inhibitors.
|
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0
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Materials that are normally stable, even under fire
conditions, and will not react with water, polymerize, decompose ,
condense, or self-react. Non-explosives.
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Personal
Protection
|
|
o
This is by far the largest area of difference
between the NFPA and HMIS® systems. In the NFPA system, the white area is
used to convey
special hazards whereas HMIS® uses the white section to indicate what personal protective equipment
(PPE) should be used when working with the material.
Note: The
NPCA specifically recommends that "preparers
of MSDSs should not place HMIS® PPE designation codes on the MSDSs or
labels that leave the facility, as they do not know the conditions under
which their customers use those products." However, these still
turn up on some MSDS's.
HMIS® uses a letter coding system for this
section. We at ILPI find this unacceptable because we would rather see the
PPE listed explicitly instead of having employees try to remember a bunch of
codes or consult a chart, something that could lead to confusion and/or a
fatal accident. Likewise, the "custom codes" aspect is particularly
dangerous for visitors and contractors who may not remember/recognize that
these could vary from job site to job site.
|
Note: Some of the
letters/symbols used in this table are also used as TSCA, CHIP, and/or DoD HMIRS/HCC codes, all
of which have completely different meanings and applications! Say, did we
tell you we dislike code systems?
|
We present the lettering scheme here, along with
a series of graphics meant to reinforce the meaning of each letter:
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HMIS® Letter
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Required
Equipment
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A
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B
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C
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D
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E
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|
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F
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|
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G
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|
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H
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I
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J
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K
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L through Z
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Site-specific label. Ask your
supervisor or safety specialist for handling instructions
|
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MSDS Laboratory Assignment
(Please submit your form with
this assignment Place numbers in label below.)
Student Name: _____________________________
Compound: ________________________________
Chemical Formula: _________________________
Appearance
& Odor: ________________________
Boiling Point:
_______ Melting Point: ________
Solubility in water:
__________________________
Conditions to
Avoid:_________________________
___________________________________________
Materials to
Avoid: __________________________
Using Chemical Date Bases
on the next page fill in the above form in your Lab Notebook and submit by the
second lab period.
MSDS
Laboratory Assignment
List of Compounds
and Elements
1. calcium
chloride
2. sodium
sulfate
3. barium
chloride
4. hydrochloric
acid
5. sulfuric
acid
6. nitric
acid
7. naphthalene
8. sucrose
9. potassium
chloride
10. silver
nitrate
11. sodium nitrate
12. ethanol
(ethyl alcohol)
13. nickel
sulfate (nickel II or nickleous sulfate)
14. copper
sulfate (copper II or cupric sulfate)
15. magnesium
sulfate
16. iodine
17. magnesium
18. magnesium
oxide
19. 2-propanol
(isopropanol or isopropyl alcohol)
20. sodium
hydroxide
21. ammonia or
ammonium hydroxide
22. aluminum
chloride
23. magnesium
chloride
24. boric acid
25. phosphoric
acid
26. ascorbic
acid (Vitamin C)
27. silicon
dioxide (sand)
28. camphor
29. sodium
bicarbonate
30. sodium
acetate
31. methyl
alcohol (methanol)
32. formaldehyde
(Methanal)
33. Benzene
34. acetic acid
(Ethanoic acid)
Some chemical information sites to
research your assigned chemical:
Oxford
University: http://msds.chem.ox.ac.uk/#MSDS
Internet Resources for MSDS: http://www.ilpi.com/msds/index.html#What
University
of Akron Date Base: http://ull.chemistry.uakron.edu/erd/
Otherwise apply a web search for MSDS and find your
chemical’s data on the web.
MSDS
Sample – Acetone on next page
Significant Figures in the Laboratory
by
Dr. David Summers, USAF Academy
Quantitative
observations in chemistry laboratory work routinely include measurements of such
quantities as masses, volumes, and temperatures.
Despite the apparent diversity of these measurements, they all share one
general feature that’s important to notice.
They all involve the reading of a
scale – the markings on a graduated cylinder, a meter stick, a beam
balance, an optical scale, etc. Many
instruments in the modern laboratory have digital readouts. You should not be lulled, however, into
thinking that they are absolutely accurate, since somewhere, at some time, the
digital scale was calibrated by a human being reading a scale.
The thermometer at
the right will serve for our present discussion.
Read this thermometer and write
your reading down here: _________°C. (Do
it NOW!)
Without being able
to peek over your shoulder, it’s hard to discuss your actual measurement, but a
safe bet would be that your answer is “24-point-something.” Assuming that the marks on the thermometer
were correctly placed, we can say that the “2” and the “4” are known with total certainty.
However, more can
be said about the temperature. You would
probably agree that the reading is not as high as 24.9 °C, and it is certainly
higher than 24.0 °C, or something in this neighborhood. Maybe the best answer would be 24.3 ± 0.1 °C, indicating the apparent doubt we
have about how far the mercury is between 24 °C and 25 °C. Our best guess for the number is 24.3, and the uncertainty is
about ± 0.1.
Before continuing,
an important definition: We will say that the Celsius temperature is
known to three
significant figures.
The number of significant figures is
found by looking at the position of the first digit in the uncertainty (the
tenths position in this example) and then counting all the digits in the number
(from the left) up to and including this position.
Sometimes significant figures are explained
by saying that we count all the digits whose certainty is known (“2” and “4”)
plus the first uncertain digit (the “3”). This can be misleading, however,
because if the reading is 24.9 ±
0.1, then the “ones” digit is not certain (it is “4” in 24.8 and 24.9, but it
is “5” in 25.0), but the “best guess,” 24.9, still has three significant
figures.
Chances are that
you know your weight to three significant figures also. “I weigh about 152 pounds” suggests that your
actual weight might be 150-154 pounds or so.
The uncertainty is about ± 2, in the ones position. The number 152 has 3 digits up to and
including the ones position, or 3 significant figures.
If this is where things
ended with significant figures, all that we would have is a definition to play
with, but there is more –
General Assumptions Regarding Significant Figures
1. Notice that the number of significant
figures is determined by the person doing the measuring. You need to decide the uncertainty in your
scale readings. Naturally, however, if
the instrument is out of adjustment, there will be “built-in” error or
uncertainty that you might not be aware of.
In some cases, this might reduce the number of significant figures you
can claim to have, just as a badly-sighted rifle would reduce target practice
scores. In Chemistry, we assume
“well-sighted rifles,” so the uncertainty is presumed to be something between
you and the scale you are staring at.
This assumption is not always justified – in some cases, you may want to
blame the instrument or procedure itself for errors you find. Fine!
Just supply evidence and reasons!
2. Notice
that in everyday life, you tend to follow an unspoken, intuitive rule:
Stop a numerical expression when you reach the position
of the first digit of uncertainty. A
person says “I weigh about 155 pounds.”
He doesn’t say, “I weigh about 155.2386439 pounds.” You followed this
intuitive rule with your thermometer reading by stopping at the tenths
position. All we ask is that you continue to follow
this unspoken guideline in chemistry. Stop a numerical expression when you reach
(roughly speaking) the first uncertain digit.
3. Notice, also, in everyday life people assume
when they hear a numerical expression that the last digit is the only
uncertain one. If you are told that
the road you are looking for is 4.6 miles ahead on the right, you would be a
little upset to miss the turn, only to discover that it was 3.6 miles instead. If the person had said “about four miles,”
you might have started looking for the road earlier. Since the tenths were expressed, you assumed
that the “4” was known with certainty – just because that’s the way we
intuitively operate. Again, all we ask is
for you to make the same assumption. The
first uncertain digit is the last one expressed. If you say the magnesium ribbon is 18.46
centimeters long, we will take the “1” and “8” and “4” to be certain, but will
assume the “6” is a little doubtful – therefore we declare there are “four
significant figures.”
Multiplication
and Division
Now, let’s look at
what happens when we want to multiply or divide numerical measurements. A student measures a rectangular piece of
tile, and reports the measurements:
Length: 15.1 cm; Width: 3.2 cm.
What, then, is the area of the tile surface?
Here is the way one
student worked the problem on a calculator:
Area = (Length) x (Width). A = (15.1 cm) x (3.2 cm) = 48.32 cm2.
The student was quite
happy with “48.32 square centimeters.” This answer, however, is not only
incorrect, but downright dishonest!
Remember that the
last digit reported is the uncertain one.
The honest length is 15.1 ± 0.1 cm, and the honest width is 3.2 ± 0.1
cm. (The uncertainties might even be
larger than this.) The area of the tile could
conceivably be (15.2 cm) x (3.3 cm) = 50.16 cm2. At the other extreme, the area could be (15.0
cm) x (3.1 cm) = 46.5 cm2.
So what are we
certain about in this answer? The area could
vary from over 46 to 50 cm2, simply due to the doubt that is always
built into judging distance between scale markings. The calculated number is 48.32 cm, but the
uncertainty is about ± 1.8 cm. Since the
first position in the uncertainty is the ones position, that is where the value
of the area should “stop,” therefore the correct answer must be “48 cm2.” Everything after the doubtful 8 must be
chopped off. It is dishonest to report
48.32 cm2, simply because that would imply that the first uncertain
digit is in the hundredths place. You
just don’t know anything approaching this much certainty about the number. If you want higher precision, the only way to
get it is to make more precise measurements.
Carrying out things to greater extremes on paper when you calculate is
simply self-deception and a waste of time.
Another example:
7 sf 3 sf 3 sf
(21.00000) x
(3.00) = 63.0 (NOT 63.00000!!)
The same rules
holds true for division:
21.00000 / 3.00 = 7.00
(Our answer is
limited to three significant figures by the 3.00.) If you are multiplying and dividing together,
things still work the same way:
[(2.000) x (4.1) x (10.0000000)] / 3.00000 =
27 (NOT 27.3333333!!)
Here we are
limited by the two significant figures in 4.1!
Zeros
as Significant Figures
We have been
implying that the number 10.0 has three significant figures. If the person went to the trouble of putting
the zero after the decimal point, there must have been a reason for it; this
just happens to be the first uncertain digit, we assume. This is fine.
(Of course, many students just add zeros to add zeros, so we have to
follow the rules so we know that 10.0 does indeed have three significant
figures.)
How many
significant figures are there in 10,000 yr?
If this represents the estimated time since the last Ice Age, it’s
fairly clear that there are five significant figures here! In other words, we are uncertain by more than
± 1 year – in fact, the uncertainty is probably more than hundreds of years,
maybe even thousands of years.
How would you
express 10,000 yr to indicate that this might be uncertain by, say, at least a
few hundred years? You can’t chop the
last two zeros – they are needed to represent the size of the number. This is the best way: 1.00 x 104
yr. In scientific notation we simply
leave those zeros that we wish; we are showing three significant figures in
1.00 x 104; 10,000 to two significant figures would be 1.0 x 104.
Now work this
problem: (10.0) x (10.0) = ??? Well, the answer should have three
significant figures, and the answer is obviously “one hundred.” But if you write 100, you are leaving the
reader to wonder whether any of the zeros are significant.
Solution: 1.00 x 102.
How many
significant figures are there in 0.00033?
Before you think too far here, put the number in scientific notation:
3.3 x10-4. Now how many significant
figures are there? Both expressions have
two significant figures. Apparently the
only function of those left-hand zeros in 0.00033 is to keep the decimal point
where it belongs. Zeros to the left of
all other numbers are never significant; they are only
place-holders.
To summarize, here
are some examples of significant figure determinations:
|
4.00030
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6 significant
figures
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0.00300
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3 significant
figures
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1.02050
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6 significant
figures
|
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10,000.0
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6 significant
figures
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10,000
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? significant
figures (ambiguous; could be 1-5)
|
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10.000
|
5 significant
figures
|
If you fail to understand
any of these examples, check with your instructor.
Rounding Off
If we wish to
express the number 326.337 to four significant figures, we would write
326.3. To make it have 3 significant
figures, since the first nonsignificant figure is less than 5, we simply drop
it. How would you express the same
number to two significant figures?
320? 330? 3.2 x 102? 3.3 x 102? Here, the first nonsignificant figure we are
dropping is greater than 5 – the number is closer to 330 than 320. But “330” fails to tell us whether the zero
is significant. 3.3 x 102 is
the clearest answer.
Suppose we wish to
express the number 37.52 to two significant figures. Here the first nonsignificant figure being
dropped is 5 and it is followed by a non-zero digit, 2. Since the 2 is the second nonsignificant
figure, it contributes nothing in helping us make our decision. In fact, we treat 37.52 as though it were
37.50. So, do you round up or round
down? Example: Express 37.50 to two significant
figures. It is clear there is not really
a best way of operating here, since 37.50 is just a close to 37 as it is to
38. Many scientists decide in cases like
this to round to the even digit. This
rule simply guarantees that over a large number of “round-offs” about half the
time we would round up, and half the time round down. Thus 38.5 to two significant figures would
also be 38. However, 39.5 would be rounded
up to 40, so that the last digit of the number, the zero, is an even number. Using this rule, you will never get an ODD number when you
round off a number ending in 5. It is
expected that you will follow this rule for any rounding that you do.
Final Comments on Significant Figures
1. Learn the rules – they save time – but remember
that the only justification for all of this business is to avoid saying more
about a calculated value than you can possibly know. It should be admitted that “significant
figures” are only a simple shortcut for indicating the uncertainty of numbers;
if you pursue this topic further, you will discover cases where “significant
figures” give you incorrect estimates of uncertainty. This should not diminish their routine
utility; as long as you “think significant figures”
you will avoid gross misstatements of uncertainty (and save yourself a lot of lost points). You should not have to ask “How far do I
carry my answers out?” Stop when you
reach the first position of uncertainty.
2. Textbook authors and problem writers
routinely violate significant figure rules.
You will probably notice this more than once in this course. Be assured that we fully intend to
consistently follow our own advice, and we will expect you to do the same –
particularly on laboratory calculations and on homework and tests.
3. What is the “rule” for adding and
subtracting numbers with significant figures? Well, there really isn’t any, if you insist
on referring to significant figures.
But, there is a simple way of knowing how to round off your addition and
subtraction results:
|
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2.34000
|
=
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2.3
|
|
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0.001
|
=
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0.0
|
|
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4.3
|
=
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4.3
|
|
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10.82
|
=
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10.8
|
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+
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3.37
|
=
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3.4
|
|
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?
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20.8
|
Round off each
term to the first position of uncertainty in any number that contains an
uncertain digit. Then add.
(Or add the numbers first, and then round back to the least amount of
decimal places in any numerical value that was included in the calculation.) In either case, you have avoided extending
things beyond the first uncertain digit.
4. Please keep in mind that this entire
discussion has been limited to numbers involved with scale-reading type
measurements. There are other kinds
of numbers – particularly counting numbers or defined numbers –
which can lead you astray if you blindly follow rules.
For example, there are exactly 12 in a dozen. The number “12” has what amounts to an
infinite number of significant figures: 12.00000000000……. and so on.
There are exactly 1000 milliliters in a liter, because we define
it to be that way.
If you count 23 people in a room, that is assumed to be exactly
23.
These kinds of numbers can never
limit the number of significant figures in any calculated result from multiplying
or dividing. Thus: If I count exactly 144,000 nails, then
that is 12,000 dozen nails, exactly, even though you might think that
144,000/12 should be carried out to only two significant figures. Similarly, in converting 1.0612 liters to
milliliters I would calculate (1.0612 L)(1000 mL/L) = 1061.2 mL The number of significant figures (5) in the
answer is limited by the number of significant figures in 1.0612 L, NOT
by the number 1000, which in this example is an exact number.
Lab Instructor Comment:
Please review Chapter 2 in your Lecture 1025 textbook for the
discussion of Significant Figures. See Chapter 1 in CHM 1032C. Dr
Summers has an excellent handout and he has given us permission to use any of
his handouts here at FSCJ.
