1. II. Units of Measurement
CH. 2 - MEASUREMENT
II. Units of Measurement

2. A. Number vs. Quantity
Quantity - number + unit
UNITS MATTER!!

3. B. SI Units Quantity Symbol Base Unit Abbrev. Length l meter m Mass m
kilogram kg
Time t
second s
Temp T
kelvin K
Amount n
mole
mol

4. B. SI Units Prefix Symbol Factor mega- M 106 kilo- k 103 BASE UNIT ---
100
deci- d
10-1
centi- c
10-2
milli- m
10-3
micro- 
10-6
nano- n
10-9
pico- p
10-12

5. M V D = C. Derived Units 1 cm3 = 1 mL 1 dm3 = 1 L
Combination of base units.
Volume (m3 or cm3)
length  length  length
1 cm3 = 1 mL
1 dm3 = 1 L
D = M V
Density (kg/m3 or g/cm3)
mass per volume

6. D. Density
Mass (g)
Volume (cm3)

7. Problem-Solving Steps
1. Analyze
2. Plan
3. Compute
4. Evaluate

8. D. Density V = 825 cm3 M = DV D = 13.6 g/cm3 M = (13.6 g/cm3)(825cm3)
An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass.
GIVEN:
V = 825 cm3
D = 13.6 g/cm3
M = ?
WORK:
M = DV
M = (13.6 g/cm3)(825cm3)
M = 11,200 g

9. D. Density D = 0.87 g/mL V = M V = ? M = 25 g V = 25 g 0.87 g/mL
A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid?
GIVEN:
D = 0.87 g/mL
V = ?
M = 25 g
WORK:
V = M D
V = g
0.87 g/mL
V = 29 mL