UNIT 1A:
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. Know and explain the difference between
accuracy and precision.
3. Begin to learn the metric prefixes.
4.Distinguish between accuracy and precision.
Page 1
TYPES OF OBSERVATIONS AND
MEASUREMENTS – PAGE 21
• We make QUALITATIVE observations of reactions —
changes in color and physical state.
• We also make QUANTITATIVE observations that
involve MEASUREMENTS with numbers and units.
ACCURACY & PRECISION –
PAGE 21
Page 2
Lab
Equip
What does Precision
it measure?
Estimated
Value
50 mL
cylinder
Burette
ruler
250 mL
beaker
Balance
125mL Flask
MEASUREMENT? – PAGE
22
Page 3
Measure These!
Page 4
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 –
PAGE 21
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
Page 5
METRIC PREFIXES – PAGE 36
METRIC PREFIXES YOU NEED TO KNOW – PAGE 36
Page 6
METRIC PREFIXES – PAGE 36
You Will Need to Know:
The Grand Master King Henry Died by
Drinking Chocolate Milk Monday Night
Prior
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)
Page 7
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.
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.
Page 8
LEARNING CHECK
Match
L) length
M) mass
V) volume
____ A.
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.
M
L
M
V
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
Page 9
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
a) mm
b) cm
c) dL
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
Page 10
c) kilometers