Measurement
In
Chemistry
Measurement
At the conclusion of our time
together, you should be able to:
1. Explain the difference between the two types
of observations
2. Give examples of 5 basic SI measuring units
3. Give examples of 3 different derived units
from the basic SI units
4. Vary the amounts of the SI measuring units
with 10 different prefixes and define each
5. Explain the difference between mass and
weight
6. List and explain 5 different units for volume.
Types of Observations and
Measurements

We make QUALITATIVE observations of
reactions — changes in color and
physical state.

We also make QUANTITATIVE
observations that involve
MEASUREMENTS with numbers and
units.
Some Tools for Measurement
Which tool(s)
would you use to
measure:
A. temperature
B. volume
C. time
D. weight
Stating a Quantitative Measurement
In every measurement there is a
Number (Quantity) followed by a
 Unit from a measuring device
Quantitative Measurements in
Chemistry Must Include Units!
Standards of Quantitative
Measurement
When we measure, we use a measuring tool to
compare some dimension of an object to a
standard.
For example, at one time the
standard for length was the
king’s foot. What are some
problems with this standard?
SI Measurement
Le Système International
d‘Unités
 Adopted in 1960 by the
General Conference on
Weights and Measures.
 International Standards are
kept in France.
 Among countries with nonmetric usage, the U.S. is the

only country significantly
holding out. The U.S.

officially adopted SI in 1866.
Liberia and Myanmar are
changing over.
Liberia
Information from U.S. Metric
Association
Base SI Units
Quantity
Unit
Symbol
Length
meter
m
Mass
kilogram
kg
Temperature
kelvin
K
Time
second
s
Amount of
Substance
mole
mol
Luminous Intensity
candela
cd
Electric Current
ampere
a
Units Of Measurement You Must Know
Use SI units — based on the metric system
Length
Mass
meter, m
kilogram, kg
Volume
Time
Temperature
liter, L
seconds, s
kelvin, K
Unit for Length
1 Meter
Note: Not Foot!!
Metric Prefixes

Kilo- means 1000 of that unit
1


kilometer (km) = 1000 meters (m)
Centi- means 1/100 of that unit
1
meter (m) =
100 centimeters (cm)
1
dollar =
100 cents
Milli- means 1/1000 of that unit
1
meter (m) =
1000 millimeters (mm)
Metric Prefixes
Metric Prefixes
You Will Need to Know:
Grand Master King Henry Died by
Drinking Chocolate Milk Monday Night
Metric Prefixes You Need to Know
103
103 meters = 1 km
1 meter (m)
1 dm (decimeter)
1 cm (centimeter)
1 mm (millimeter)
10
1
10-1
10-2
10-3
10 dm = 1 m
100 cm = 1 m
103 mm = 1 m
1 m (micrometer)
10-6
106 m = 1 m
1 nm (nanometer)
10-9
109 nm = 1 m
1 kilometer (km)
Unit for Mass
1 Kilogram
Note: Not Gram!!
Unit for Weight
1 Newton
1 N = kg m/s2
A Weighty Problem
On 9/23/99, $125,000,000 Mars Climate Orbiter
entered Mars’ atmosphere 100 km lower than planned
and was destroyed by heat.
1 lb = 1 N
1 lb = 4.45 N
“This is going to be the
cautionary tale that will be
embedded into introduction
to the metric system in
elementary school, high
school, and college science
courses ‘till the end of time.”
Mass and Weight
Weight is force of the gravitational pull on an object. It
would be different on the moon than it is on earth.
Mass is a measure of the amount of matter in an object.
Mass and weight are directly related as long as we remain on
earth at the same elevation. That is, if one object has twice
the mass of another, then its weight on earth would also be
twice as large.
However, if we take the same object to Denver, Colorado,
the mass stays the same but the weight would be
different. Why??
Mass vs. Weight
Mass: Amount of
Matter
 (grams, measured
with a BALANCE)
 Weight: Force
exerted by the
mass, only
present with
gravity
 (pounds,
measured with a
Scale)

Can you hear
me now?
Unit for Volume
1 Meter Cubed
Note: A Derived Unit!!
To Big, So Generally Use the Liter
What is a Liter??
Length and Volume
1 m = 10 dm
therefore
1 m3 = 103 dm3
1 dm = 10 cm
therefore
1 dm3 = 103 cm3
1 L = 1 dm3
and
1 L = 103 mL
so
1 L = 1 dm3 = 103 mL = 103 cm3 = 103 cc
so
This means that 1 milliliter (mL) is the same as
1 cubic centimeter (cc). These terms are often
used interchangeably.
Units for Volume
m3
cm3
1 dm3 = 1 L
dm3
L
mL
Liter
1 cm3 = 1 mL
Other Derived SI Units
Quantity
Unit
Symbol
Volume
cubic meter
m3
Density
kilograms per cubic
meter
kg/m3
Speed
meter per second
m/s
Newton
kg m/ s2
N
Energy
Joule (kg m2/s2)
J
Pressure
Pascal (kg/ms2)
Pa
Units for Energy

Joule

calorie
J
1 cal = 4.184 J
1 cal = quantity of heat needed to raise the
temperature of 1 g of water by 1 oC.
1 kcal = 1000 cal
Measurement
Let’s see if you can:
1. Explain the difference between the two types
of observations
2. Give examples of 5 basic SI measuring units
3. Give examples of 3 different derived units
from the basic SI units
4. Vary the amounts of the SI measuring units
with 10 different prefixes and define each
5. Explain the difference between mass and
weight
6. List and explain 5 different units for volume.
Learning Check
Match
L) length
M) mass
V) volume
M A.
____
A bag of tomatoes is 4.6 kg.
L B.
____
A person is 2.0 m tall.
M C.
____
A medication contains 0.50 g Aspirin.
V D.
____
A bottle contains 1.5 L of water.
Learning Check
What are some U.S. units that are used to
measure each of the following?
A. length
B. volume
C. weight
D. temperature
Which Metric Prefix is Generally Used?
Learning Check
1. 1000 m = 1 ___
a) mm
b) km
c) dm
2.
0.001 g = 1 ___
a) mg
b) kg
c) dg
3.
0.1 L = 1 ___
a) mL
b) cL
c) dL
4.
0.01 m = 1 ___
a) mm
b) cm
c) dm
Learning Check
Select the unit you would use to measure
1. Your height
a) millimeters
b) meters
c) kilometers
2. Your mass
a) milligrams
b) grams
c) kilograms
3. The distance between two cities
a) millimeters
b) meters
c) kilometers
4. The width of an artery
a) millimeters
b) meters
c) kilometers