1. Ch. 2 - Measurement I. Units of Measurement Number vs. Quantity
SI Base Units & Prefixes
Derived Units
Density Calculations

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

3. B. SI Units Quantity Base Unit Symbol Length meter m Mass kilogram kg
Time
second s
Temp
kelvin K
Current
ampere A

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

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

6. D M V D. Density V = 825 cm3 M = DV D = 13.6 g/cm3
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 = 11,220 g D M V

7. D M V D. Density D = 0.87 g/mL V = M V = ? M = 25 g V = 25 g 0.87 g/mL
1) 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 D M V
V = g
0.87 g/mL
V = 28.7 mL

8. D M V D. Density M = 620 g D = M V = 753 cm3 D = ? D = 620 g 753 cm3
2) You have a sample with a mass of 620 g & a volume of 753 cm3. Find density.
GIVEN:
M = 620 g
V = 753 cm3
D = ?
WORK:
D = M V D M V
D = g
753 cm3
D = 0.82 g/cm3