Chemistry is the study about how matter
is put together, how atoms combine to
form molecules, and how the molecules
combine to make up the many kinds of
matter around us.
Classification of Matter
 Matter – identified and organized by properties
 anything that has mass and takes up space
 Properties
 Chemical – ability to react/combine (both what
it will and won’t react with)
- will change the composition
 Physical – characteristics observed or measured
-will not change the composition
 two kinds of physical properties help describe the
behavior of a substance undergoing a physical change
1. Extensive- depends on the amount of matter
Ex: mass, length, volume
2. Intensive- does not depend on the amount of
Ex: density (regardless of size, each sample of a
substance has the same density) color, crystalline
shape, melting point, boiling point, phase of the
matter (solid, liquid, gas), and refractive index
(ability of material to bend light)
Property
Physical or
Chemical
Intensive or
Extensive
Size
P
E
Density
P
I
Color
P
I
Flammable
C
N/A
Corrosive
C
N/A
Phase of matter
P
I
State (or phase) of matter is always a
physical property: Solid, liquid, gas
Phase
Energy
– move
Particle
spacing
Volume
Shape
Compressible
Solid
Little
Definite
Definite
No
Liquid
Some
Close
Rigid
Close
Slide
Definite
Not
Definite
No
Gas
Lot
Far
Not
Definite
Not
Definite
Yes
Changes in Properties
 Physical change - does NOT change the
composition (identity) of the substance. Same
substance remains after a change has taken place
*Size: pounding, bending, grinding, pulling, or
cutting does not change the chemical character
of a substance.
*Change of state: melting, boiling, vaporizing
*Cutting a piece of wood into smaller pieces,
tearing paper, dissolving sugar in water,
hammering copper into a new shape are all
examples of physical change.
Chemical changeDOES change
composition. After a
change has taken place
a new substance
appears
 Changes that
produce a new kind
of matter with new,
different properties.
Burning, digestion,
fermenting all form
new substances with
new and different
characteristics.
 Sodium- a silvery, soft
metal that reacts
vigorously with water
(Na)
 Chlorine- a yellow-green
gas that is highlycorrosive and poisonous
(Cl)
 Yet if these two elements
are brought together,
they combine to form a
white crystalline solid.
Table salt (NaCl), which
neither reacts with water,
nor is poisonous.
1. Heat and/or light is produced
2. Production of a gas (bubbles)
3. Odor
4. Color change
5. Formation of a precipitate – a cloudy solid
which appears after mixing to clear
solutions
 Chemical Reactions - a Chemical change has taken
place: 2 or more substances have chemically bonded
together to create a new substance
 Law of Conservation of Mass – matter is neither
created nor destroyed. This states that mass remains
constant during a chemical reaction. One of the
greatest scientific achievements of the 18th century by a
Frenchman, Lavoisier (1743-1794)
Mass (of reactants) =
Before
Mass (of products)
After
Chemical Equations:
Reactant + reactant  product + product
(always on left)
(always on right)
~ arrow shows directions
Ex. 12 g of calcium reacts with 6 grams of fluorine gas to
produce calcium fluoride. How many grams of
product will be produced?
12 g Ca + 6 g F2  ____ g CaF2
(12 + 6)
= (18)
Try it
 Separating water turns into hydrogen gas and oxygen
gas. If 10.0 g of hydrogen and 79.4 g of oxygen are
produced, how much water did was there at the start?
____ g H2O  10.0 g H2 + 79.4 g O2
89.4 g H2O  10.0 g H2 + 79.4 g O2
 Mixture- matter that contains two or more
different materials
 Phase- any region with a uniform set of properties
Ex: sour milk, watery part is one phase while
fat is the second phase
Mixtures are divided into two
categories
 1. Heterogeneous
mixture- a
mixture that is
composed of
more than one
phase
 Ex: granite, sand
 2. Homogeneous mixturematerials that consist of only
one phase.
 If you break a piece of
homogeneous matter into
smaller pieces, each piece
will have the same properties
as every other small piece
 Ex: seawater, window glass,
and air
Separating Mixtures
(physical separation)
1. Filtration – through a porous barrier,
filters solids from liquids
2. Distillation – different boiling points
2 liquids: lowest boiling point vaporizes 1st
3. Crystallization – dissolved solids from a solutions
rock candy left after water evaporates
4. Chromatography – different rate of travel through a
medium
identify chemicals, DNA testing, separates pigments,
research
 Pure Substances- homogeneous materials
that always have the same composition
 *Homogeneous mixtures are not pure
substances, yet the substances that comprise
them are evenly dispersed throughout the
mixture
Pure Substances are divided into
two categories
 2. Compounds 1. Elementssubstances composed
of only one kind of
atom (elements on the
P.T.)
 Ex: sodium ~ Na, Iron
~ Fe, Neon ~ Ne
composed of more
than one kind of atom
(made from multiple
elements on the P.T.)
 Ex: water ~ H2O, table
salt ~ NaCl
 Compounds cannot
be physically
separated, they are
chemically bonded
Matter
1.
2.
Mixtures
Homogeneous
Mixture
Pure Substances
Heterogeneous
Mixture
Suspension
Element
1.
2.
Solutions
1.
2.
3.
Colloid1.
Compound
1.
2.
3.
2.
Matter
1. Has Mass
2. Has Volume(Occupies Space)
Mixtures
Homogeneous
Mixture
Pure Substances
Heterogeneous
Mixture
Suspension
Element
1.
2.
Solutions
1.
2.
3.
Colloid1.
Compound
1.
2.
3.
2.
Mixtures
Variable Composition
Can be physically separated
Homogeneous
Mixture
Heterogeneous
Mixture
Uniform Throughout
(But Proportions can
Vary)
Solutions
1. Particles are atoms,
ions, or molecules
2. Won’t scatter light
3. Ex. Salt Water, Steel, Air
Not uniform Throughout
Ex. Lumpy
ColloidDon’t settle out
1.
2.
3.
Particles larger than
molecule
Scatters light
(Tyndall Effect)
Ex. Smoke, Fog
Suspension
Solid in Liquid
Eventually settle out
Ex. Muddy water
Wood, granite,
blood
Pure Substances
Definite Composition
Homogeneous
Can’t be physically separated
Element
Compound
1.
2.
Chemical combinations
of 2 or more atoms.
(elements chemically
bonded)
Cannot by separated by
physical means (CaCl2,
NaCl, Sugar, C6H12O6)
1.
2.
Made of atoms
Cannot be further
separated by
chemical or
physical means
(on periodic table
Mendeleev
arranged in
rows-periods
Columnsgroups/families)
Matter
1. Has Mass
2. Has Volume(Occupies Space)
Mixtures
Pure Substances
Variable Composition
Can be physically separated
Homogeneous
Mixture
Uniform Throughout
(But Proportions can
Vary)
Definite Composition
Homogeneous
Can’t be physically separated
Heterogeneous
Mixture
Not uniform Throughout
Ex. Lumpy
Solutions
1. Particles are atoms,
ions, or molecules
2. Won’t scatter light
3. Ex. Salt Water, Steel, Air
Colloid- Don’t
settle out
1.
2.
3.
Particles larger than
molecule
Scatters light
(Tyndall Effect)
Ex. Smoke, Fog
Suspension
Element
Solid in Liquid
1.
2.
Eventually settle out
Ex. Muddy water
Wood, granite, blood
Compound
1.
2.
Chemical combinations
of 2 or more atoms.
(elements chemically
bonded)
Cannot by separated by
physical means (CaCl2,
NaCl, Sugar, C6H12O6)
Made of atoms
Cannot be further
separated by
chemical or
physical means
(on periodic table
Mendeleev
arranged in
rows-periods
Columnsgroups/families)
Law of Definite Proportions
Regardless of amount, a compound is always composed of
the same elements in the same proportion by mass
% by Mass = Mass of element x 100
Mass of compound
 If compounds
have the same %
by mass, they
must be the same
80 g sample of compound contains 20 g of hydrogen.
What is the percent by mass of hydrogen?
20 g x 100 = 25%
80 g
 If 7 g of iron combine with 3 g of oxygen, what is the %
by mass of iron? Of oxygen?
 Hint: Find the total mass 1st
% iron = 7g x 100 = 70%
10 g
%oxygen = 3g x 100 = 30%
10g
Try it
 Sample 1 contains 15.0 g of H2 and 120.0 g of O2
 Sample 2 contains 2.0 g of H2 and 32.0 g of O2
Are they the same compound?
 Sample 1 contains 15.0 g of H2 and 120.0 g of O2
 Sample 2 contains 2.0 g of H2 and 32.0 g of O2
Are they the same compound?
Sample 1
15 g + 120 g = 135 g
Sample 2
2 g + 32 g = 34 g
H2 : 15 x 100 = 11%
135
O2 : 120 x 100 = 89%
135
H2 : 2 x 100 = 6%
34
O2 : 32 x 100 = 94%
34
Different percentages so these are different compounds
Intro to the Periodic Table
Vertical columns
Horizontal rows
 called groups or
families.
 called periods.
 Elements in a group
have similar chemical
& physical properties.
 Numbered from 1-18
from left to right
 Elements within a
period have
properties that
change progressively
across the table.
 Metals – (left side) are good conductors of heat and
electricity; shiny metallic luster (mostly silver or grayish
white); malleable (hammered or rolled into thin sheets);
ductile (string into a wire); properties vary according to
groups
 Nonmetals – (right side) elements that are poor
conductors of heat and electricity, dull (no luster); some
are gases at room temperature. Br is a liquid; C, P, Se, S & I
are solid and much more brittle than metals
 Metalloids – (on the stair-step line) – elements that have
characteristics of both metals and nonmetals to a limited
degree. Less malleable than metals, but not as brittle as
nonmetals; some have luster, some don’t; semiconductors
of electricity (used in semi-conducting materials found in
computers, calculators, watches, TV’s and radios)
Branches of Chemistry
 Organic Chem – study of carbon – containing compounds
 Inorganic Chem – all substances not classified as organic




(mainly those that do not contain carbon)
Physical Chem – the study of properties and changes of
matter and their relation to energy
Analytical Chem – identification of the components and
composition of materials
Biochemistry – substances and processes occurring in
living things
Theoretical Chem – uses math and computers to
understand the principles behind observed chemical
behavior and to design and predict new compounds