Transcript MATTER & MEASUREMENTS

MATTER & MEASUREMENTS
Learning
Math & Metric System; Numbers
Properties & Types of Matter
Precision/Accuracy
Changes
E: energy
subst: substance
w/: with
w/o: without
rxn: reaction
D: change amt: amount
Ch. 1
lays foundation to your study
Learning Chemistry
Requires you to bring together new concepts & devel new skills
Need to devel good study habits
Don’t FALL BEHIND
Focus your study
Good notes
Text material before class
Review material before class
Learn language of Chem
Make use of resources
Chem all around
impacts our lives; health care, environment, our needs
Other fields
bio, geo, engr, arts, ag
MATTER
mass & vol
3 States
Solid - def shape, def vol, not compressible
Liquid - def vol, shape of container, not compressible
Gas -vapor, not def shape/vol, highly compressible
S: molecules held
tightly in fixed
position
Physical Change
D state (s-l-g) but
not composition
D phy appearance
L: molecules close
together in random
motion
G: molecules far apart,
no specific arrangement,
move high speed, collide
w/ each other & wall
What effect does incr Temp cause?
Classification diagram, pg 11
g, l, s
MATTER
soln
Li2CO3
mass & vol
minerals
NO
liquids
HETROGENEOUS
Mixture
diff throughout
uniform
thru-out
YES
gas
CH3CH2CH3
dry cmpd
AgNO3
HOMOGENEOUS
same throughout
table salt
NaCl NO
PURE SUBST
ocean
Variable
Composition
YES
MIXTURE
SOLN
PURE SUBST
p.table
H2O ---->
H 2 + O2
NO
made
simplier
YES
ELEMENT
CMPD
not broken down
broken down
PROPERTIES
Extensive \ Intensive
additive
non-
What examples of 2 diff subst can be combined?
#1: 50 ml @ 25oC #2: 100 ml @ 50oC
volume
PHYSICAL
Physical \
Chemical
same subst
mix amts
sep phy
return
new subst
new props
sep chem
not return
Properties:
ex: taste, color, texture, size, odor, etc.
CHEMICAL
Properties:
ex: explosive, digestive, flammable
Changes
METRIC SYSTEM
Dimensional Analysis/Factor Label
factor-label method
look at the
“unit labels”
GIVEN UNIT * conversion to UNIT 
1
GIVEN UNIT
500 yd to inches?
conversion factors: 1 yd = 36 in
500 yd * 36 in  in
1
1 yd
1 yd = 3ft & 1 ft = 12 in
500 yd * 3 ft 12 in  in
1
1 yd 1 ft
Base Units
length: meters, m
mass: grams, g
volume: liters, l (L)
Mass
Based on quantity of matter present
Not affected by gravity
Relationship:
1 ml = 1 cm3
Weight
Affected by gravitational force
o ; 10-10
angstrom; A
nano; n; 10-9
10-8

10-11
pico; p; 10-12
10-7
-6
micro 10
10
-5
10-4
-3
10
m
milli
c
centi
10-2
10-1
d
deci
BASE: gram,
100 = 1
g, m, l
meter, liter
da
101
deka
hecto
h
k
kilo
Mega; M; 106
Giga; G; 109
102
103
Tera; T; 1012
How many km is 745.26 cm?
745.26 cm * 1 km
 0.0074526
1
100,000cm
1.5*106 L to kL?
1.5*106 L * 1*10-9 kL 
1
1 L
1.5*106 L * 1 kL 
1
1*109 L
TEMPERATURE SCALES
• Fahrenheit, Celsius, Kelvin
oF
= (9/5 oC) + 32
oC = 5/9(oF - 32)
K = 273.15 + oC
BOILING PT.
FREEZING PT.
oF
212o
32o
oC
100o
0o
K
373.15o
273.15o
mass per
unit vol
table densities, pg 17
temp depend
GAS: g/L
Density 
mass (g)
vol (ml or cm3)
consider 2 Fe samples
#1: 6 g @ 7.9 g/mL
#2: 4 g @ 7.9 g/cm3
Which properties are intensive?
mass or density
Measurements
exact number: all digit values known; definition or count
dozen, 12
1 ft = 12 in
2.54 cm = 1 in
inexact: uncertainty in last digit value Where do they
come from?
SIGNIFICANT FIGURES
1. All nonzero digits are significant 5.37 cm ?3 4.293g ?4
2. Zeros between nonzero digits are sig. 106 ml ?3 1.02 L ?3
3. Zeros to the right of the dec. pt. at the
end of a number are sig.
8.00 ml 3
23.0600 km 6
4. Zeros before the 1st nonzero digit in a number are not sig.
0.002 g ?1
0.060 * 10-3 mm ?2 0.00000725 L ?3
5. Zeros at the end of a whole number are sig. if a bar is over the zero;
or decimal pt shown
__
_
500 ?3
500. ?3
500 ?1
500 ?2
OPERATIONS
Add / Subtract Count decimal places (least)
32.5437
- 3.54
161.032
5.6
+ 32.4524
?
?
?
?
Multiply / Divide
Count sig. figures
5.6 * 103
= ?658.8235294 => ?660
8.50
152.06
* 0.24
?36.4944
or ?6.60*102
?36
ACCURACY & PRECISION
Accuracy
Accuracy
• How close data points to
“true” value
• 7.96
7.92
8.02
• 7.96
4.02
24.87
• Closeness of set of
collected data to the
“correct” or most
probable value
ACCURACY & PRECISION
Precision
• Closeness of set of
collected data
among the data
itself
Precision
• How close data points are to
each other; grouped
• 0.997
0.999
1.003
• 1.325
0.046
5.263
Poor accuracy & precision
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Good precision & Poor accuracy
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Good accuracy & precision
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