Chemistry
Laboratory Introduction
Always know what, and why, you are going to do before you do it. Ask the
teacher if not absolutely clear.
The rules of physics apply during a lab just as they do outside the lab.
Use common sense. (e.g., Hot objects are hot, glass breaks, liquids can spill.)
CoolKey:sg:sg.Laboratory Introduction.Student.docx
Chemistry
Laboratory Introduction
p. 1
TABLE OF CONTENTS
LABORATORY SAFETY AGREEMENT .................................................................................................. 2 GENERAL RULES TO FOLLOW DURING AN EXPERIMENT ............................................................. 3 SAFETY WORKSHEET ............................................................................................................................... 5 LIST OF LABORATORY EQUIPMENT ................................................................................................... 7 GENERAL LABORATORY PROCEDURES WORKSHEET ................................................................... 9 HOW TO MEASURE LENGTH ................................................................................................................ 10 HOW TO POUR A LIQUID ........................................................................................................................11 HOW TO MEASURE VOLUME ............................................................................................................... 12 HOW TO LIGHT A BURNER ................................................................................................................... 13 INSTRUCTIONS - FORMAL LAB WRITE UP ................................................................................................... 14 Chemistry
Laboratory Introduction
p. 2
LABORATORY SAFETY AGREEMENT
LAB
I,
____ ________ agree to abide by the following laboratory safety
regulations whenever performing a lab investigation.
I will:
1. use the science laboratory for authorized work only and will only work with the teacher’s
supervision.
2. wear a lab apron, remove contact lenses and wear safety goggles, remove dangling jewelry
and tie back long hair.
3. know the hazardous chemicals and control measures, as indicated by the teacher.
4. read the lab exercise with special notice to safety precautions before beginning the
experiment, and ask questions if the procedure is not clear.
5. know the location of safety equipment, fire extinguisher, eyewash, safety shower, and fire
blanket, and be familiar with the use of each piece of equipment.
6. in case of fire, accident or injury, alert the teacher at once.
7. never taste, touch, or smell any substance unless directed specifically by the teacher.
8. handle chemicals carefully, check the label of every bottle before removing the contents, and
never return unused chemicals to reagent containers.
9. when heating a substance in a test tube, make sure that the mouth of the test tube points away
from other people and away from myself.
10. dispose of broken glass, chemicals, and biological materials as instructed to do so.
11. at the end of the lab, clean the work area. Wash and store materials and equipment, and turn
off the water, gas, and electrical appliances.
12. never eat, drink, or chew gum in the laboratory.
Student’s Signature
Date
Parent’s Signature
Date
Chemistry
LAB
Laboratory Introduction
p. 3
GENERAL RULES TO FOLLOW DURING AN EXPERIMENT1
1. KNOW WHAT YOU ARE DOING!
• Read all directions before you start to work. Take
notes.
• When in doubt, ask the teacher to explain.
• Use only the amounts and materials listed in the
experiment.
• Make substitutes only when told to do so by your
teacher.
2. OBSERVE LABORATORY SAFETY
PROCEDURES!
• Always wear safety goggles and a laboratory apron
while working in the laboratory.
• Fasten long hair back.
• Never taste, eat, or drink anything in the laboratory.
• Immediately wash off any chemical spilled on your
skin. Flood the area with copious amounts of running
water for at least 2 minutes. Tell, or have someone
tell, the teacher immediately.
• If your skin itches or burns, flood the area of skin with water. Tell, or have someone tell, the
teacher immediately.
• Keep your face back away from containers being heated, and don't lean over your work area.
• Avoid inhaling toxic fumes by using the ventilation hood.
• Wash your hands before leaving the laboratory.
• Report all accidents to your teacher at once.
3. PREVENT ACCIDENTS FROM OCCURRING!
• Work in a quiet, businesslike manner.
• Avoid moving about the laboratory.
• Clean up spilled chemicals by first flooding them with water and then wiping them up with a
sponge.
• Keep the drawers and cupboard doors of your laboratory desk closed unless you are removing or
putting something away.
• Don't reach over a burner. (Sometimes you can't see a flame!)
• Turn off a burner as soon as you are finished heating something, and remember the iron support
ring stays hot for a while after the burner has been turned off.
• Put burned matches, broken glassware, and used chemicals in the places designated by your
teacher.
• Know where the fire extinguisher, nearest fire alarm box, fire blanket, and eyewash device are
located and how to use them.
• Report all accidents to your teacher immediately.
1
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York.
Chemistry
Laboratory Introduction
p. 4
4. AVOID CONTAMINATION OF CHEMICALS!
• Never return any excess chemical to its stock bottle (original container). Discard the extra
chemical, as you would used chemicals.
• Replace caps, stoppers and corks immediately after removing a chemical from its bottle. The
chemical may be affected by the air or moisture.
• Use only clean, dry spoons, spatulas, or scoopulas to remove solids from their containers. Rinse
and dry stirring rods before using them to stir other liquids.
• Be sure all glassware is clean before using. Drops of water will not cling to clean surfaces of
glass.
5. STUDY OBSERVATIONS BEFORE ANSWERING QUESTIONS!
• Look for differences and similarities. Hunt for "patterns" in the data.
• Think what the question means before answering it. See if the textbook (or other references)
gives you any help.
• Look up the meaning of any term you do not understand.
• Record any other questions or thoughts you may have that might lead to future
experimentation or discussion.
Chemistry
LAB
Laboratory Introduction
p. 5
SAFETY WORKSHEET2
INTRODUCTION
Because you use many chemicals in the chemistry laboratory, it is important to know something about
them. Most chemicals are dangerous – e.g., poisonous when they enter the body, burn or irritate the skin,
eyes and/or membranes of your digestive and respiratory tracts. Some chemicals destroy fabrics,
especially synthetic or protein fibers. Chemicals can even make some things burn. Generally, most
chemicals combine at a reasonable rate; however, under certain conditions they can get out of control.
Knowing these things about chemicals helps you to prevent accidents and to work safely in the
laboratory.
QUESTIONS
1. While you are working in the laboratory, why should you:
a. wear safety goggles? _____________________________________________________________
b. fasten long hair back? ____________________________________________________________
c. wear a laboratory apron? __________________________________________________________
d. use only the amounts and materials given in the directions?
_______________________________________________________________________
e. use only clean glassware? _________________________________________________________
2. Why are unused chemicals never returned to their original containers?
_________________________________________________________________________________
3. Rings and other jewelry should not be worn in the lab. Why?
_________________________________________________________________________________
4. Why are bottles of chemicals kept tightly closed except when a quantity of chemical is being
removed?
_________________________________________________________________________________
5. Why should the teacher be informed if you are wearing contact lenses?
_________________________________________________________________________________
6. Why are most chemicals stored in glass or plastic containers rather than metallic ones?
_________________________________________________________________________________
7. How should you dispose of chemicals that you used in the experiment?
_________________________________________________________________________________
8. If your skin itches, burns, or appears red while you are using chemicals, what should you do? (a) __
(b) ______________________________________________________________________
9. What procedures should you follow to:
2
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 6-8.
Chemistry
Laboratory Introduction
p. 6
a. report an accident resulting in injury to you or someone else?_____________________________
b. report spilling a chemical or breaking equipment? ______________________________________
c. cope with a fire on your laboratory bench? ___________________________________________
d. dispose of cracked or broken glassware? _____________________________________________
10. Where are the following items located in the classroom?
a. fire extinguisher: ________________________________________________________________
b. fire blanket: ____________________________________________________________________
c. shower: _______________________________________________________________________
d. eye wash device: ________________________________________________________________
11. Why are desk drawers and cupboard doors kept closed unless you are taking something out or putting
it away?
_________________________________________________________________________________
12. Why is it important to work in a business-like manner, quietly, and with a minimum of distraction or
migration around the classroom?
_________________________________________________________________________________
13. What is the meaning of the following words often found on the labels of chemicals?
a. caustic: _______________________________________________________________________
b. corrosive:______________________________________________________________________
c. hazardous: _____________________________________________________________________
d. volatile: _______________________________________________________________________
14. Why are you not allowed to eat or drink anything in the chemistry classroom?
_________________________________________________________________________________
15. Why should you read the label on a bottle twice before using its contents?
_________________________________________________________________________________
16. You should hold a bottle of liquid with the label toward the palm of your hand when you pour out the
liquid. Why?
_________________________________________________________________________________
17. A cap, cork, or stopper from a bottle of liquid is not put down on a desk while you are pouring out
some of the liquid. Why?
_________________________________________________________________________________
18. Explain the statement: “You are only as safe as the LEAST safe person in the laboratory.”
_________________________________________________________________________________
_________________________________________________________________________________
Chemistry
LAB
3
Laboratory Introduction
p. 7
LIST OF LABORATORY EQUIPMENT 3
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 4-5.
Chemistry
Laboratory Introduction
p. 8
Chemistry
LAB
Laboratory Introduction
p. 9
GENERAL LABORATORY PROCEDURES WORKSHEET4
QUESTIONS
1. Name the apparatus or glassware is used?
a. to pick up and hold apparatus?
b. to clean glassware?
c. as a cover for a beaker?
d. to transfer solid chemicals in massing?
e. as a container for small amounts of liquid being
evaporated?
or
f. to grind chemicals to a powder?
g. to measure a volume of a liquid?
h. to measure length?
i.
to measure mass?
2. What is the name for each of the following pieces of laboratory equipment?
(N.B. Objects are not shown to scale.)
4
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 8-10.
Chemistry
LAB
Laboratory Introduction
p. 10
HOW TO MEASURE LENGTH5
FINAL READING (R2) MINUS INITIAL READING (R1) = LENGTH
R1 = 1.0 cm
R2 = 7.4 cm
7.4 cm – 1.0 cm = 6.4 cm LONG
5
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 23
Chemistry
LAB
Laboratory Introduction
p. 11
HOW TO POUR A LIQUID6
Remove the cap to the bottle. Do not put cap on the counter in a way that would allow liquid on
the counter top – when you do this, you have essentially spilled chemical onto the countertop.
Moreover, when you replace the cap on the bottle, you can contaminate the liquid if there was
anything on the countertop.
Shown below is the correct way to remove the stopper to a bottle containing a liquid. A similar
®
procedure should be used if the cap is a screw-cap, parafilm wrapping, etc.
Generally, liquids can be poured carefully directly into the desired container. However, one
common technique, used especially for pouring liquids that also contain suspended solids, is
DECANTING, which is shown below.
Also, don’t hesitate to use a funnel when pouring into a small-mouth container.
6
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 17
Chemistry
LAB
Laboratory Introduction
p. 12
HOW TO MEASURE VOLUME7
1. Decide what each unmarked line represents:
A. On the above scale (Figure 1):
1) Divide :
2)
difference
amount
=
number of lines 1 line
5 mL
5 lines
= 1 mL per line
B. Look carefully at the scale. Some graduated cylinders are marked differently.
C. Read at the bottom of the meniscus (the curved
surface of the liquid).
Hold the graduated cylinder at eye level so that
it is high enough that you can’t see the back of
the nearest number.
7
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 22
Chemistry
LAB
Laboratory Introduction
p. 13
HOW TO LIGHT A BURNER8
OVERVIEW:
Fire requires three parts: (1) heat, (2) fuel, and (3) oxygen. Remove any one of these and the fire will be
extinguished. There are several styles of burners available but all share the combining of heat, fuel, and oxygen.
Gas intake can be adjusted at the main gas valve or by a valve at the base of the burner. Oxygen intake can be
adjusted at the air intake. The style of the burner and the source of heat will determine the steps you follow. Listed
below are the two most common burners and two ways for lighting either type.
The hottest part of any flame is the tip of the inner blue cone.
Figure 1.
Fischer Burner
1. Use rubber tubing to connect the burner to the gas valve. Make sure that the
chimney is lowered and just snug (no he-man tightening: it will strip the threads),
or that the collar is closed. This will make it easier to light the gas.
2. Turn on the main gas valve.
3. Strike the striker and ignite the gas. (If you smell gas, turn off the main gas valve
and wait a couple of minutes for the odor to dissipate.)
4. Adjust the height of the flame with the burner gas valve (Figure 2) – again, just so
it is snug or you will damage the valve.
Figure 2.
5. Adjust the air intake to obtain a blue cone (Figure 1).
Bunsen Burner
1. Use rubber tubing to connect the burner to the gas valve. Make sure that the
chimney is lowered and snugly tight (no he-man tightening: it will strip the
threads), or that the collar is closed. This will make it easier to light the gas.
2. Strike match.
3. Turn on the main gas valve.
4. Bring lighted match up to the chimney to ignite the gas. (If you smell gas, turn off
the main gas valve and wait a couple of minutes for the odor to dissipate.)
5. Adjust the height of the flame with the main gas valve. Adjust the air intake (by
raising/lowering chimney or by adjusting the air intake) to obtain a blue cone
(Figure 1).
8
Figure 3.
Bolton, Ruth P., Lamphere, Elizabeth V., and Menesini, Mario. (1979). Laboratory Experiments in ACTION CHEMISTRY. Holt, Rinehart and
Winston, Publishers, New York. p. 22
Chemistry
Laboratory Introduction
p. 14
INSTRUCTIONS - FORMAL LAB WRITE UP
LAB
Your lab report should be five sections as detailed below. Each section must be appropriately labeled. A
guideline for each section contained in each section is given below following some overall instructions..
OVERALL INSTRUCTION
•
Use the passive voice. Avoid the first person pronouns I, we, my, you, they. This includes the past
tense – hopefully, you are writing the lab after you did it.
o
Example: Water, 30 mL, was added to the sample. (Active: I added 30 mL of water to the
sample.)
•
•
•
•
•
The word data is plural; its singular is datum.
Sentences do not begin with a number (e.g., “30 mL of water were added” is better written “Water, 30
mL, were added.”). In the text body, the numbers zero through ten are written; 11 and above are
given as numbers.
Common abbreviations are as follows and need not be explained. Other abbreviations and chemical
formulas may be used provided they are explained when first used (e.g., nitric acid (HNO3)).
units:
liters (L)
grams (g)
meters (m)
prefixes:
milli- (e.g., mL)
centi- (e.g., cg)
kilo- (e.g., km)
Format of the pages: borders are 1” (top, bottom, left and right). Font is conservative (e.g., Arial 10,
Courier 10, or Times New Roman 11 point). Line spacing is 1.5 lines.
Use spell check but do not assume it is faultless.
SPECIFIC SECTIONS
1. Title
•
The title should reflect the purpose of the lab. It should be succinct, unambiguous and descriptive.
Example: Compositional Analysis of Hydrated Copper Sulfate
2. Purpose
•
This single sentence summarizes the purpose of the lab. It is acceptable to include the phrase “The
purpose of this lab was to…”
Example: The purpose of this lab was to determine the chemical formula for hydrated copper
sulfate.
3. Introduction
•
•
•
This is an explanation of the underlying background and theory needed to understand the
importance and relevance of the lab.
Address your audience with the knowledge you had the day you were handed the directions for the
experiment. Discuss any relevant information that you researched, discussed in class, or read in the
textbook. Make the experiment relevant to your daily life. Explain the purpose of the lab and how
it can be applied to material being covered in the class and outside the lab in daily life. Include the
reason for doing the lab and what is to be learned from it.
Include, and clearly label, the independent variable, dependent variable, and control(s).
Chemistry
Laboratory Introduction
Component
• independent variable
•
•
dependent variable
•
control
Description
the thing that you change
(what I do)
the thing that changes as a
result of what you do (it
depends on what is done)
factors that remain constant
throughout the
experiment; test with a
known outcome
p. 15
Example
how much water you give to the
plants
the amount of plant growth in two
weeks
the amount of light; giving the plant
the amount of water specified in
the seed package
A Hypothesis should also be clearly labeled and provided. It is not a guess. It is a logical proof
starting with a given assumption (or assumptions) passing through a series of logical arguments and
leading to a proposed experimental outcome. To accomplish this, you will need to have a clear
understanding of what you are doing in the experiment and why you are doing it.
4. Materials and Method
•
Materials
o
This is the recipe from which another student can replicate what you did and get same results
you got.
o
List the equipment and supplies that are required to complete the lab. Frequently, this is given
to you in the lab handout. List the major pieces of equipment first – the item is given and then
its quantity (e.g., test tubes, 10 mm x 160 mm, x3). Then list common and consumable (e.g.,
chemicals) items.
Method
•
o
This step-by-step process is given in a list of sequentially steps. Be very exact and descriptive.
It is assumed that the first step is to “gather all materials” and the last step is “clean up.” Do
these in the actual laboratory experiment but don’t write them in the write-up.
Safety
•
o
Identify any special precautions or concerns.
5. Data / Results
•
•
•
Data are the observations – either qualitative (e.g., “the color of the solution is red”) or quantitative
(e.g., 3.40 g). Quantitative measurements are also called measurements. Results are data that have
been submitted to calculations. For example, the masses of the (a) empty test tube and (b) test tube
with sample are data. The mass of the sample (b – a) is a result. [The word data
Data are recorded in a table(s). Results can be included in the data table (e.g., the mass of the
sample) or in graphs. Graphs are visual representations of the data and results so that they can be
easily studied, interpreted and analyzed.
Use bar graphs for discontinuous data; x-y graphs for continuous data. For x-y graphs, use the
‘best-fit’ line (a.k.a., best-fit curve) – don’t connect the dots. Your data are based on actual
measurements and, therefore, have inherent errors.
Chemistry
Laboratory Introduction
Data Type
Examples
Graph Type
Continuous
temperature, time
x-y graph
p. 16
Example
30
25
20
15
10
5
0
0
Discontinuous
Mg, Zn, Cu, Fe
bar graph
1
2
3
4
5
6
30
25
20
15
10
5
0
1
•
2
3
4
5
Every graph should have a title, x-axis (units) label, and y-axis (units) label.
6. Analysis / Discussion
•
This is the written summation of what you learned from the experiment. THIS IS THE MOST
IMPORTANT PART OF THE LAB WRITE-UP.
•
Information in the above sections of the write-up can, are often, repeated.
•
The following outline is a guide to help you in writing up this section.
Restate the purpose of the lab in your own words.
Summarize your hypothesis.
Describe briefly how the purpose of the lab was undertaken – e.g., a one- or two-sentence
summary of the lab procedure.
Describe what you found. Restate the major results, interpret them in the context of class
material and discuss their importance. Don’t try to “prove” anything – the data either support
your hypothesis or they don’t. Discuss the actual data as well as the general trend(s). What is the
significance of your findings? Be specific. MAKE YOUR POINT!
Discuss your errors and possible implications. How valid are your results? This includes
quantitative (e.g., percent error and/or recovery) and qualitative evaluations. State what worked in
the experiment and what didn’t. Give specific examples. Provide suggestions on how you would
do the experiment differently next time, and additional experiments. Did you do replicates? How
valid was your control?
Demonstrate that you understood the experiment.
7. Conclusion
•
This is a one- to two-sentence summary of what you did and what you found. It is not a
personal statement of whether you enjoyed the experiment or learned a lot. It is an objective
statement summarizing your work.
Chemistry
NOTES:
Laboratory Introduction
p. 17