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CHAPTER 1
AP CHEMISTRY
TYPES OF MATTER
► PURE
SUBSTANCE
 the same throughout
►
ELEMENTS
 Fixed properties, substance cannot be broken
down chemically
►
COMPOUNDS
 Two or more elements chemically bonded, fixed
properties, can be broken down chemically
PHYSICAL PROPERTIES/CHANGES
► Properties
 Can be measured and will usually be the same
 Color, density, boiling point, melting point, hardness
►
Change
 Properties remain the same throughout a physical
change
►
Phase change
 Solid, liquid, gas
►
Mass or volume change
CHEMICAL PROPERTIES/CHANGES
► Properties
 The way a substance reacts with another
substance
►
Changes
 Identity of the substance is altered
MIXTURES
► HOMOGENEOUS
 Uniformly mixed, all in the same phase
►
HETEROGENEOUS
 Not uniformly mixed, different phases
►
CAN BE SEPERATED BY PHYSICAL MEANS
MEASUREMENTS PAGE 8
► LENGTH
►
BASIC UNIT - METER
 1m = 102 cm = 10-3km
 1nm = 10-6 mm = 10-9 m
 Common unit prefixes - kilo, centi, milli, nano
►
►
MASS
BASIC UNIT KILOGRAM
 COMMON PREFIXES
 Kilo, milli, mega
TEMPERATURE
► UNIT
 CELSIUS - oC
 FAHRENHEIT - OF
 KELVIN - K
Temperature is the factor that determines
the direction of heat flow
► Temperature is measured indirectly by
measuring its effect upon the properties of
a substance
►
RELATIONSHIP BETWEEN CELSIUS
AND FAHRENHEIT
► Celsius
and Fahrenheit when compared to
each other form a linear line
 y = mx + b
B = y when x is 0
 m = y2 - y1 Tf = Tc(9oF/5oC) + 32
►
x2 - x1
Boiling and melting points
CELSIUS AND KELVIN
► Kelvin
is known as the absolute scale, used in
chemistry
 0K = -273.15 oC
 TK = TC + 273.15
ENERGY
► SI
unit is Joule
 1J = 1 N.m = 1 kg.m2/s2
► Relationship between calories and Joules
 1cal = 4.184 J
► PROPERTIES
 INTENSIVE
 The value is not dependent on the amount of
material you have
► EXTENSIVE
 Depends on the amount
UNCERTAINITY IN MEASUREMENTS
► Every
measurement has a degree of uncertainty.
Human error or balances that are calibrated
differently.
► ACCURATE
 How close the measurements are to the “true”
value
► PRECISION
 How close an individual measurement is to
other measurements
DERIVED UNITS
► VOLUME
 SI unit is m3
 1cm3 = (10-2 m)3 = 10-6 m3
 1L = 1000 mL =1000 cm3
► FORCE
 SI unit is Newton
 1N = 1kg.1m/s2
► PRESSURE
 SI unit is Pascal
 1Pa = 1N/m2
 Standard atmosphere is 1.013 x 105 Pa
SIGNIFICANT FIGURES
► ATLANTIC-PACIFIC
RULE
 If a decimal point is Present then count the
significant figures from the left (Pacific side). Start
with the first nonzero number ----> 0.07302
 If a decimal point is Absent then count the
significant figures from the right (Atlantic side).
Start with the first nonzero number 40978000 <-
SIGNIFICANT FIGURES
►
►
►
State of degree of confidence in the measurement cited
Nonzero integers:
 Nonzero integers are always significant
Zero’s. There are three classes or zero’s
 Leading zero’s precede (before) all nonzero digits. ARE
NOT SIGNIFICANT 0.0025
 Captive zero’s are between two nonzero digits. ARE
SIGNIFICANT 1.109
 Trailing zero’s are to the right of nonzero integers.
ONLY SIGNIFICANT IF A DECIMAL POINT IS PRESENT
57000 and 57000.
ROUNDING NUMBERS
►
►
►
In a series of calculations carry all digits unit the final
solution, THEN ROUND
If a digit needs to be rounded
 If it is less than 5, the preceding digit remains the
same
If the digits are equals or is greater than 5, the preceding
digit is increased by one.
UNCERTAINITY IN NUMBERS
►
►
Multiplication and division
 Significant figures are the same as the least precise
(number with the smallest number of significant figures)
measurements
Addition and subtraction
 The answer will have the same number of digits
beyond the decimal point as the integer (that was
added or subtracted) with the least accurate number
(last significant number is in the highest place holder)
PERCENT ERROR
► When
doing an experiment it is important to
see if you did it correctly. This can be done
if an accepted value is known. (i.e. density
of copper 8.9 g/mL). You compare your
value to the accepted value by using percent
error
► Percent = │accepted value - experiment value│
x 100
Error
accepted value
DENSITY, MELTING AND BOILING
POINTS
►
DENSITY
 Mass/volume, unit = g/cm3
►
Melting point
 Temperature at which solid goes to liquid phase
►
Boiling point
 Temperature at which liquid goes to gas
►
Solubility
 Different compounds have different solubility's at different
temperatures
►
Usually solubility of a solid goes down as the temperature
goes down (except KOH)