Transcript Let`s Get Started!!

Let’s Get Started!!
Chapter 1- start to
finish
CHEMISTRY

The science that deals with the
materials of the universe and the
changes that these materials
undergo
Wood burns
 Plants grow
 Iron rusts
 Bread bakes
 Human digestion

The Scientific Method






State the problem
Make observations
Form a hypothesis
Perform an experiment
Make observations
Develop a Law


Develop a theory



A summary of observed behavior
An explanation of behavior
Continue to experiment
Modify theory as needed
Important Terms

Matter


Mass



Amount of space an object occupies
Qualitative observations


Amount of matter in an object
The measure of the resistance of an object to a change
in its state of motion
Volume


Anything that has mass and volume
Observations not requiring measurements
Quantitative observations

Observations requiring measurements
Weight!?!
 The
force that gravity exerts
 In chem (or in AP) all our
measurements will be on earth
(we hope!) so weight & mass
are interchangeable.
Volume?
Fundamental Units
 Mass
 kg
 Length
m
 Time
s
 Temp
K
Fundamental Units
 Electric
current
 Amt of
substance
 Luminous
intensity
A
 mol
 cd
Prefixes Used in SI
system
 Kilo
 103
 deci
 10-1
 centi
 10-2
 milli
 10-3
Prefixes Used in SI
system
micro
-6
10
nano
10-9
Uncertainty of Measurement
 Gold
costs $5.75 for .01 g
 Mass ring- 7.62 g
 Dealer
says- 8 g
What’s the problem?
The
decimal places are
SIGNIFICANT!!
Numbers are significant
when…
1. They are NOT zero!
2. They are exact numbers
 Conversions,
numbers
pi, counted
Numbers are significant
when…
 Zeros
1. Captive zeros- YES
2. Leading zeros- NO
3. Trailing zeros- YES
Multiply and Divide
Number
of sig figs in
answer is same as
number with least
number of sig figs
Add and Subtract
 Result
has same number
of decimal places as
number with least decimal
places in calculation
Number of Sig Figs?
1056
4
1000
1
100.0
4
.00350
3
Some Math…
 2.002
X 3.42 X 5 =
 703.2+34.223–21.45
 34.2
30
= 716.0
X 25.3 + 1.332 = 866
Play some darts…
Precision
Degree
of agreement
among several
measurements
Accuracy
Degree
of agreement
of a particular value
with the accepted
value
Error?? What error?
 Random
 Equal
low
error
chance of being high or
 Systematic
 Same
error
direction each time
Dimensional Analysis
 UNIT
FACTOR METHOD!
 A student entered a 12.0
km run. How many miles
is it?
Temperature
 Three
scales
 Fahrenheit
 Celsius
 Kelvin
Density
Mass/Volume
Classification of matter
MATTER
has mass and volume
PURE
SUBSTANCES
Can write chemical formula
ELEMENT
One type of atom
COMPOUND
Two or more different
atoms chemically bonded
MIXTURES
Variable ratio
HOMOGENEOUS
solutions
HETEROGENEOUS
Colloids and suspensions
Physical and Chemical
Properties and Changes

Physical Property


Physical Change


A change that does not affect the composition
of the substance
Chemical Property


Characteristics that describe a substance
Characteristics that refer to the ability to form
new substances
Chemical Change

A change which produces new substances
Separation Techniques
 Distillation
 Filtration
 Chromatography