Chapter 5
Sections 5.2-5.3
Units of Measurement
Mrs. Baldessari
Chemistry
Objectives: Use the metric system to
measure length, volume, and mass
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.
Measurement
You are making a measurement when you
Check you weight
Read your watch
Take your temperature
Weigh a cantaloupe
What kinds of measurements did you make
today?
Some Tools for Measurement
Learning Check
From the previous slide, state the tool (s) you
would use to measure
A. temperature
____________________
B. volume
always use a
____________________
never use a
____________________
C. time
____________________
D. weight
____________________
Solution
From the previous slide, state the tool (s) you
would use to measure
A. temperature
thermometer
B. volume always use a: graduated cylinder
never use a: Beaker
C. time
stop watch
D. weight
scale
Measurement in Chemistry
In chemistry we
do experiments
measure quantities
use numbers to report measurements
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
Solution
Some possible answers are
A. length
inch, foot, yard, mile
B. volume cup, teaspoon, gallon, pint, quart
C. weight
ounce, pound (lb), ton
D. temperature F
Metric System (SI)
 Is a decimal system based on 10
 Used in most of the world
 Used by scientists and hospitals
Units in the Metric System
 length
meter
m
 volume
liter
L
 mass
gram
g
 temperature
Celsius
°C
Stating a Measurement
In every measurement there is a
Number
followed by a
 Unit from measuring device
Quantitative Measurements in Chemistry
Must Include Units!
Learning Check
What is the unit of measurement in each of the
following examples?
A. The patient’s temperature is 38.8 °C .
B. The sack holds 2.3 kg of potatoes.
C. It is 12.8 km miles from your house to
school.
D. The bottle holds 2 L of orange soda.
Solution
A.
°C (degrees Celcius)
B.
Kg (Kilograms)
C.
Km (Kilometers)
D.
L (liters)
Learning Check
Identify the measurement in metric units.
A. John’s height is
1) 1.5 yards
2) 6 feet
3) 2 meters
B. The volume of saline in the IV bottle is
1) 1 liters
2) 1 quart
3) 2 pints
C. The mass of a lemon is
1) 12 ounces
2) 145 grams
3) 0.6 pounds
Solution
A. John’s height is
3) 2 meters
B. The volume of saline in the IV bottle is
1) 1 liter
C. The mass of a lemon is
2) 145 grams
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.
Stating a Quantitative Measurement
In every measurement there is a
Number (Quantity) followed by a
 Unit or label from a measuring device
Remember: No naked numbers
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?
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 or centimeter
Note: Not Foot or inches !!
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 You Need to Know
The pneumonic:
King Henry Died Unexpectedly
Drinking Chocolate Milk
Memorize
this!
You must also know…
…how to convert within the Metric
System. Here’s a good device:
On your paper draw a line and add 7
tick marks:
Next:
Above the tick marks write the abbreviations for
the King Henry pneumonic:
k
h
d
(u )
d
c
m
m
l
g
Write the units in the middle under the “U”.
Let’s add the meter line:
k
h
d
u
d
c
m
km
hm
dam
m
L
g
dm
cm
mm
Let’s add the liter line:
k
h
d
u
km
kL
hm
hL
dam m
daL L
g
d
dm
dL
Deca can also be dk or da
c
cm
cL
m
mm
mL
Let’s add the gram line:
k
h
d
u
km
kl
kg
hm
hl
hg
dam m
dal
l
dag g
d
c
m
dm
dl
dg
cm
cl
cg
mm
ml
mg
How to use this device:
1. Look at the problem. Look at the unit
that has a number. On the device put
your pencil on that unit.
2. Move to new unit, counting jumps and
noticing the direction of the jump.
3. Move decimal in original number the same
# of spaces and in the same direction.
Example #1:
(1)
Look at the problem. 56 cm = _____ mm
Look at the unit that has a number. 56 cm
On the device put your pencil on that unit.
k
h
km
hm
d
u
dam m
d
dm
c
cm
m
mm
Example #1:
2. Move to new unit, counting jumps and
noticing the direction of the jump!
k
h
d
u
km
hm
dam m
d
dm
c
cm
One jump to the right!
m
mm
Example #1:
3. Move decimal in original number the same
# of spaces and in the same direction.
56 cm = _____ mm
56.0.
One jump
to the right!
Move decimal one jump to the right.
Add a zero as a placeholder.
Example #1:
56 cm = _____ mm
56cm = 560 mm
Example #2:
Look at the problem. 7.25 L = ____ kL
Look at the unit that has a number. 7.25 L
On the device put your pencil on that unit.
(1)
k
h
d
kl
hl
dal
u
L
d
c
m
dl
cl
ml
Example #2:
2.
Move to new unit, counting jumps and
noticing the direction of the jump!
k
h
d
kl
hl
dal
u
L
d
dl
c
cl
m
ml
Three jumps to the left!
Example #2:
(3) Move decimal in original number
the same # of spaces and in the same
direction.
7.25 L = ____ kL
.007.25
Three jumps
to the left!
Move decimal to the left three jumps.
Add two zeros as placeholders.
Example #2:
7.25 L = ____ kL
7.25 L = .00725 kL
Example #3:
Try this problem on your own:
45,000 g = ____mg
k
h
d
kg
hg
dag g
u
d
dg
c
cg
m
mg
Example #3:
k
h
kg
hg
d
dag
u
g
d
dg
c
m
cg
mg
Three jumps to the right!
45,000.000.
Example #3:
45,000 g = 45,000,000 mg
Three jumps to the right!
Example #4:
Try this problem on your own:
5 cm = ____ km
k
h
d
km
hm
dam
u
m
d
dm
c
cm
m
mm
Example #4:
k
h
d
km
hm
dam
u
m
d
dm
Five jumps to the left!
.00005.
c
cm
m
mm
Example #4:
5 cm = .00005 km
Five jumps to the left!
Examples #5-9:
Solve these five problems on your
own. Show your answers to your
teacher.
You may choose to use the King Henry
Notes.
You may choose the King Henry
Staircase.
You may also choose to make a King
Henry Slider.
Examples #5-9:
(5) 35 mm = ____ cm
(6) 14,443 L = ____ kL
(7) 0.00056 kg = ____ g
(8)35.4 L = ____ mL
(9)16 mm = ____ km
One last caution:
Be careful NOT
to count the
spot you start
from, where you
put your pencil
point.
Only count
the jumps!
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)
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
•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!!
Too Big, So Generally Use the Liter
What is a Liter??
Length and Volume
1 m = 10 dm
1 dm = 10 cm
1 L = 1 dm3
therefore
therefore
and
1 m3 = 103 dm3
1 dm3 = 103 cm3
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) or 1 cm3. These terms are often used
interchangeably.
Units for Volume
m3
cm3
1 dm3 = 1 L
dm3
L
mL
Liter
1 cm3 = 1 mL
Measuring Volume:

The volume of a liquid is
measured with a graduated
cylinder. When liquid is
poured into the cylinder, a
curved surface called the
meniscus is formed.
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
____ A.
M) mass
V) volume
A bag of tomatoes is 4.6 kg.
____ B. A person is 2.0 m tall.
____ C.
A medication contains 0.50 g Aspirin.
____ D.
A bottle contains 1.5 L of water.
Learning Check
Match
L) length
_M
__ A.
M) mass
V) volume
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.
Which Metric Prefix is Generally Used?
Put a star by the appropriate measurement
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
1. 1000 m = 1
___
2.
0.001 g = 1
___
3.
0.1 L = 1
___
4.
0.01 m = 1 ___
a) mm
a) mg
b) km
b) kg
c) dm
c) dg
a) mL
b) cL
c) dL
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
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
Complete 1-10 metric measurement worksheet