Download Classification of Matter

Classification of
Matter
Physical Science
Four classes of matter
 The
four classes of
matter are elements,
compounds,
mixtures, and
solutions
Homogeneous matter
 Appears to look similar
throughout
 Ex: salt, sugar,
whipped cream
 all parts are alike
(appearance)
Question
 What
does the prefix
“homo” mean?
 Name the four classes of
matter.
 What are the four phases
of matter?
Question
 Milk
in most stores is
homogenized. What
do you think this
means?
Heterogeneous matter
 Matter
that has
different properties
 Ex: soil, cereal with
raisins, concrete
Question
 How
is homogeneous
matter different from
heterogeneous matter?
Question
 Why
is it better to
classify matter
according to make-up
rather than phase?
Think!
What is a mixture?
 A combination of
substances
 Two or more
substances that are
not chemically
combined
Properties of mixtures
 The substances in a
mixture keep their
separate identities
(properties)
 Ex: salt/pepper,
sugar/water
Separating mixtures
 The
substances in a
mixture can be
separated by simple
physical means
 Evaporation and
filtration are used to
separate mixtures
Types of mixtures
 Heterogeneous
mixtures are the “least
mixed” of all mixtures
 The different particles
in mixtures are large
enough to be seen
Homogeneous mixtures
 Homogenous
mixtures
are “well mixed”
 Particles are small and
not easily recognized
Question
 What
are two ways
mixtures can be
separated?
Solutions
A
solution is a
mixture in which a
substance is
dissolved in another,
“best mixed”
Properties of a solution
 Particles are not large
enough to be seen
 Evenly spread particles
 Particles cannot be
separated by simple
physical means
Alloys (video)
 Solutions
of metals are
alloys
 Ex: gold jewelry, brass,
sterling silver,
stainless steel
Questions
 Describe
an alloy.
 What are two
properties of a
solution?
Pure substances
 Homogeneous matter
is also known as a pure
substance
 Properties: one kind of
material with the same
properties
Elements
 Simplest types pure
substances
 Made of only one type
of atom
 Cannot be broken down
by chemical processes
or heating
What is an atom?
 The
smallest particle
of an element that
has the same
properties of the
element is the atom
Chemical symbols
 A short way of
representing elements
 Consists of one or two
letters
 An abbreviation for an
element
Question
 What
are two
properties of
elements?
 What is an atom?
Compounds
 Pure substances made
of more than one
element is a compound
 Ex: carbon dioxide,
ammonia, sugar
Molecules
 Two
or more atoms that
are chemically bonded
 Smallest part of a
compound that has the
same properties of that
compound
Separating compounds
 Compounds are made
of molecules
 Compounds can be
broken down into
simpler substances by
heating and electricity
Questions
 How
is a molecule
different from an atom?
 How is a compound
different from an
element?
Chemical formulas
 Combinations
of
chemical symbols
are chemical
formulas (C3H7OH)
(NH3)
Subscript
 A subscript is placed to
the lower right of the
chemical symbol
 It gives the number of
atoms of the element
Questions
 How
is chemical
symbol different from a
chemical formula?
Chemical equations
A
description of a
chemical reaction
using symbols and
formulas is a
chemical equation
Coefficient
 The
number used to
balance a chemical
equation (coefficient)
 “Balanced” means the
same number of
reactants and products
Questions
 How
is a subscript
different from a
coefficient?
Chemical reactions
 Reactants
are the
substances that enter a
chemical reaction
 Products are the
substances formed by a
chemical reaction
Chemical equations
 2H2+O2 (reactants)
2H2O
 The arrow means yields
(makes)
 C + O2  CO2 (products)
 Reactants (yield)
products
Questions
 What
does the arrow 
mean in a chemical
equation?
 What is a chemical
equation?
Questions
 What
is another name for
a chemical reaction?
 On what side of a
chemical reaction would
you find the reactants?
 Products?