Matter – Properties and
Changes
Chapter 3
States of Matter
Solids





Definite shape
Definite volume
Particles are very tightly packed
together
Incompressible – cannot be pressed
into a smaller volume
When heated it expands only
slightly
States of Matter
Liquids





Constant volume
Takes the shape of its container
Is a fluid (it flows)
Particles are less closely packed
together than in a solid
Particles are able to move past each
other
States of Matter
Gases





No constant volume
No constant shape
Is a fluid (it flows)
Particles are very far apart from
each other
Particles are very easily compressed
Properties of Matter



Substance – matter that has a
uniform and unchanging
composition
Ex: table salt, sugar
The formula for table salt is always
NaCl, it never changes. It is always
made up of one sodium atom and
one chlorine atom.
Physical Properties



Characteristic that can be observed
or measured without changing the
samples composition
Extensive properties – dependent
upon the amount of a substance
Ex: mass, length
Intensive properties – not
dependent upon the amount of a
substance
Ex: density, color
Chemical Properties

The ability of a substance to
combine with or change into
another substance
Ex: Iron reacts with oxygen to
form rust
Ex: Sodium reacts with chlorine to
form table salt
3.2 - Changes in Matter


Physical Changes – Changes that
alter a substance without changing
its composition
Ex: cutting a piece of paper
Chemical Changes – A process that
involves one or more substance
changing into a new substance.
The new substance has new
properties and a new composition.
Ex: burning wood
Conservation of Mass

The total mass involved in a
chemical reaction remains constant
Law of Conservation of Mass–
mass is neither created nor
destroyed during a chemical
reaction
Mass
reactants
= Mass
products
Law of Conservation of Mass
Example:
Mercury II oxide yields mercury + oxygen
216 g
 200g
+ 16 g
 Both sides of the arrow need to be the same
H2O

H2 +
Xg

10 g + 79.4 g
Xg

89.4 g
O2
(solve for x)
3.4 Elements and Compounds
Elements – a pure substance which
cannot be broken down into simpler
substances
 Elements have a unique chemical
name and formula and are all on
the periodic table
 Symbol consists of 1-3 letters and
the first is always capitalized
Periodic Table
The periodic table organizes the
elements based on similarities
 Horizontal rows – periods
 Vertical columns – groups or
families (elements in the same
group have similar physical and
chemical properties)
 Put together by Mendeleev – he left
blank spots for elements that were
not yet discovered.
Compounds
Compounds- a combination of two or
more elements that are chemically
combined.
 Most of the matter in the universe is
a compound – water, salt, aspirin
 We use chemical symbols to write
formulas for chemical compounds
Ex: NaCl
sodium chloride (salt)
Compounds
Unlike elements compounds can be
broken down
 The properties of a compound are
different than those of the elements
it is made of
Ex: H2O – water – liquid @ room
temperature, stable
H2 and O2 - gases @ room
temperature, reactive

Mixtures of Matter
Mixtures – combination of two or
more pure substances in which each
substance retains its individual
chemical properties
Which is a mixture?
Water and sand 
Water and salt 
Y or N
Y or N
Types of Mixtures
Heterogeneous Mixtures – one that
doesn’t blend smoothly throughout
and in which the individual
substances remain distinct
Ex: Water and sand
Can you think of others?
Types of Mixtures
Homogeneous Mixtures – constant
composition throughout; always has
a single phase
Ex: water and salt
 Also known as solutions
 Don’t always have to be liquids
Ex: steel – iron and carbon alloy