Student Name_____________________________
Partner’s Name____________________________
Date____________________________________
General Chemistry, 1025C
Review of Safety and SI Units Lab-SL
Part I: Laboratory Rules and Safety Guidelines
Reread through the Laboratory rules and safety guidelines then complete the following questions:
True or False, mark T or F, and answer.
1. ______Tank tops and sleeveless tops are appropriate clothing for the laboratory.
2. _____ Above the knee shorts are permitted in the laboratory along with open toe shoes.
3. _____ Simple accidents such as breaking a beaker containing distilled water do not need to be
reported to the instructor.
4. _____ It is the student’s responsibility to print out the lab and read it prior to lab class unless
instructed otherwise.
5. _____ You may wear headphones and listen to music while working in lab.
6. _____ The instructor is responsible for providing the students with goggles.
7. _____ It is okay to leave the burner on for a minute while I walk away to weigh a sample.
8. _____ Lab reports are due the following lab period at the end of the lab period.
9. _____ Calculations do not need to be shown in lab reports.
10. _____ Grammar and spelling do not count in your lab report grade.
11. _____ Lab report calculations must be done individually.
12. _____ Goggles must be worn at all times during the lab. Failure to do so will result in one warning
and then significant point loss and even lab expulsion.
13. _____ Failure to follow lab rules may result in lab expulsion.
14. _____ Students do not need to check out their lab with the instructor prior to leaving lab.
15. _____ Students do not need to check out their locker with the instructor or lab assistant prior to
leaving lab.
Part II: Le System International d’Unites (SI Units)
The SI, is a modern versions of the metric system. It provides a logical system of measurements and is
accepted throughout the world by scientists and engineers. The SI system has seven base units. The base
unit for mass is the kilogram (kg). The base unit for length is the meter (m). The SI system uses the Base
10, so it is easy to convert from one unit to another.
Kilo
Hecto
Deka
Base Unit
Deci
Centi
Milli
k
h
D
g, m, l, s, etc
d
c
m
1000 base = 1 kilo
100 base = 1 hecto
10 base = 1 Deka
10 deci = 1 Base
100 centi = 1 Base
1000 milli = 1 Base
1
Other bases:
Femto
Pico
Nano
Micro
f
p
n
µ
1
1
1
1
Mega
Giga
M
G
1 x 106 base = 1 Mega
1 x 109 base = 1 Giga
x
x
x
x
1015 femto = 1 Base
1012 pico = 1 Base
109 nano = 1 Base
106 micro = 1 Base
Conversion of measurements requires the use of the Factor-Label Method (Dimensional Analysis). This
method is an easy way to move from one unit to another. Many students feel they do not need to use the
Factor-Label method when converting within the SI system because they are comfortable simply moving the
decimal point. The problem with this is that we will soon be doing more difficult problems where moving the
decimal point is no longer our only concern. In addition, as the problems get more difficult, it is easy for
students and experienced problem solvers to lose track of their progress in the solution process. As a result, I
require all students to learn and use the Factor-Label method. Failure to do so will result in complete loss of
points for your work. In addition, you must show all work, every single step in order to receive full credit.
JUST DO IT!!!!
There are two main rules to solving science problems with the factor-label method:
Note that your text calls this method dimensional analysis.
1. Always carry along your units with any measurement you use.
2. You need to form the appropriate labeled ratios (equalities).
Example Problem:
How many centimeters in 2.0 meters?
You will see from the metric conversion chart that 1 meter = 100 cm
We turn this into a ratio by writing it like this:
OR
Once you have the equality written as a fraction, you must pick the one that will cancel out the units leaving
the desired units.
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Then multiply your starting quantity (2.0 meters) by the equality that will give you your desired units. For
example:
2.0 m x 100 cm = 2.0 x 102 cm
1m
As a rule of thumb your problem set up should look like this:
It is that simple.
Sometimes you will need to multiply by more than one ratio to get to your desired units, you can do this by
using linking units. Your setup will look like this:
For example, given that 1 inch = 2.54 cm, how many m are in 3.5 inches?
3.5 in. x 2.54 cm x 1 m = 0.089 m
1 in.
100cm
For the above example, you needed to convert from the English system of units to the SI system. For
problems such as these, it is helpful to have a table of common conversions.
Table of Conversion Factors:
Physical Quantity
Length
SI Unit
Meter (m)
Volume
Cubic meter (m3)
Mass
Kilogram (kg)
Pressure
Pascal (Pa)
Temperature
Energy
Kelvin (K)
Joule (J)
Conversion Factor
1 km = 0.6215 mi.
1 in. = 2.54 cm
1 mi. = 1.6093 km
1 mi. = 5280 ft.
1 L = 1.057 qt.
1 L = 1 dm3
1 fluid oz. = 29.57 ml
1 lb = 453.6 g
1 kg = 2.205 lb.
1 lb = 16 oz.
1 Pa = 1 N/m2
1 atm = 101.325 Pa
1 atm = 760 torr
1 atm = 14.70 lb/in2
K = 273.15 + ˚C
1 cal = 4.184 J
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Answer the following questions on separate paper. Label the section. Show all work.
You must use the factor label method (dimensional analysis). You must use the correct
number of significant figures and put the correct unit after each answer.
1. Convert each of the following:
a) 2.63 m to km
b) 250.0 mL to L
c) 9.04 mg to hg
d) 13.445 s to cs
2. The width of a football field is 53.0 ft and 4.0 inches.
a) First convert this width to total inches.
b) Next convert the total inches to m.
c) Finally convert the total m to miles.
3. Determine the volume in mL of 17.5 teaspoons.
Hint: 1 Tablespoon = 3 teaspoons, 1 Tablespoon = 0.5 fluid oz.
4. A new penny has a mass of 2.49 g.
a) Convert this measurement to mg.
b) Convert this measurement to pounds.
5. The heat required to raise the temperature of a 1 gram of lead 1 degree Celsius is 0.128 Joules.
Convert this quantity from joules to calories.
6. An aspirin tablet has a mass of about 81.0 mg.
a) Calculate the total mass of aspirin tablets in a 250 tablet bottle in mg.
b) Calculate the total mass in g.
c) Calculate the total mass in ounces.
7. How many minutes are there in 34.5 years? Note 1 year is 365.25 days.
8. The height of the Statue of Liberty from the base to the torch is 46.50 m. What is the height
expressed in miles?
9. The length of the Statue of Liberty’s nose is 1.48 m.
a) What is this length in cm?
b) What is this length in inches?
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