1. Measurement
and
Chemistry

2. Measurement is central to chemistry
Metric system: the set of units used for scientific measurements.
SI Units: there are seven base SI units and all other units are derived from these.

3. Base Units of Measurement (SI UNITS: International System)
Measurement Unit Name Abbreviation
Mass Kilogram kg
Length Meter m
Time Second s
Temperature Kelvin K
Amount Mole mol

4. Length and Mass
Note the SI unit for length is the meter (m) whereas the SI unit for mass is the kilogram (kg).
1 kg weighs lb

5. Mass and weight Mass is the amount of “stuff” (matter) in a material.
To measure use a balance.
Weight is the amount of stuff measured by gravity. On earth mass and weight are the same. To measure use a scale.

6. Derived Units of Measurement
Volume
The units for volume are given by (units of length)3.
SI unit for volume is 1 m3.
We usually use a non-SI unit for volume: liter or milliliter
1 mL = 1 cm3.
1 L = 1 dm3 = 1000 mL.

7. Other Units of Measurement
(Non-SI Units)
Measurement Unit Name Abbreviation
Pressure atmosphere atm
millimeters of mercury mm Hg
pascal Pa
Temperature Celsius C
Energy calorie cal
Joule J

8. Unit Conversions

9. A. SI Prefix Conversions
1. Find the difference between the exponents of the two prefixes.
2. Move the decimal that many places.
To the left
or right?

10. A. SI Prefix Conversions=
532 m = _______ km
0.532
NUMBER
UNIT
NUMBER
UNIT

11. A. SI Prefix Conversions
Symbol
Factor
mega- M
106
kilo- k
103
BASE UNIT
---
100
deci- d
10-1
move left
move right
centi- c
10-2
milli- m
10-3
micro- 
10-6
nano- n
10-9
pico- p
10-12

12. A. SI Prefix Conversions
0.2
1) 20 cm = ______________ m
2) L = ______________ mL
3) 45 m = ______________ nm
4) 805 dm = ______________ km 32
45,000
0.0805

13. B. Dimensional Analysis
The “Factor-Label” Method
Units, or “labels” are canceled, or “factored” out

14. B. Dimensional Analysis
Steps:
1. Identify starting & ending units.
2. Line up conversion factors so units cancel.
3. Multiply all top numbers & divide by each bottom number.
4. Check units & answer.

15. B. Dimensional Analysis
Lining up conversion factors:
= 1
1 in = 2.54 cm
2.54 cm cm
1 =
1 in = 2.54 cm
1 in in

16. B. Dimensional Analysis
How many milliliters are in 1.00 quart of milk? qt mL
1.00 qt
1 L
1.057 qt
1000 mL
1 L
= 946 mL 

17. B. Dimensional Analysis
You have 1.5 pounds of gold. Find its volume in cm3 if the density of gold is 19.3 g/cm3. lb
cm3
1.5 lb
1 kg
2.2 lb
1000 g
1 kg
1 cm3
19.3 g
= 35 cm3

18. B. Dimensional Analysis
How many liters of water would fill a container that measures 75.0 in3?
in3 L
75.0 in3
(2.54 cm)3
(1 in)3
1 L
1000 cm3
= 1.23 L

19. B. Dimensional Analysis
5) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? cm in
8.0 cm
1 in
2.54 cm
= 3.2 in

20. B. Dimensional Analysis
6) Taft football needs 550 cm for a 1st down. How many yards is this? cm yd
550 cm
1 in
2.54 cm
1 ft
12 in
1 yd
3 ft
= 6.0 yd

21. B. Dimensional Analysis
7) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? cm
pieces
1.3 m
100 cm
1 m
1 piece
1.5 cm
= 86 pieces