Transcript II. Units of Measurement

CH. 2 - MEASUREMENT
II. Units of Measurement
I
(p. 33 - 39)
II
III
C. Johannesson
A. Number vs. Quantity
 Quantity - number + unit
C. Johannesson
UNITS MATTER!!
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
C. Johannesson
B. SI Units
Prefix
mega-
Symbol
M
Factor
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-
C. Johannesson
p
10-12
C. Derived Units
 Combination of base units.
1 cm3 = 1 mL
length  length  length
1 dm3 = 1 L
 Volume (m3 or cm3)
 Density (kg/m3 or g/cm3)
mass per volume
C. Johannesson
M
D=
V
D. Density
Mass (g)
Δy M
D

slope 
Δx V
Volume (cm3)
C. Johannesson
Problem-Solving Steps
1. Analyze
2. Plan
3. Compute
4. Evaluate
C. Johannesson
D. Density
 An object has a volume of 825 cm3 and a
density of 13.6 g/cm3. Find its mass.
GIVEN:
WORK:
V = 825 cm3
D = 13.6 g/cm3
M=?
M = DV
M
D
V
M = (13.6 g/cm3)(825cm3)
M = 11,200 g
C. Johannesson
D. Density
 A liquid has a density of 0.87 g/mL. What
volume is occupied by 25 g of the liquid?
GIVEN:
WORK:
D = 0.87 g/mL
V=?
M = 25 g
V=M
D
M
D
V
V=
25 g
0.87 g/mL
VC. Johannesson
= 29 mL