Transcript Properties and Changes of Matter

Chemistry
Chapter 3
Properties and Classification
of Matter
Chemistry-Matter and Change
Glencoe
Last revision Fall 2007
Matter
Matter – anything that has mass and volume.
Mass – the amount of material that makes an
object
Volume – the amount of space an object takes
up
Your textbooks?
Light from
a
lighthouse?
The pen/pencil you
are writing with?
Your thoughts?
Heat from
a fire?
All matter is made of tiny little particles called
atoms.
There are 90
different naturally
existing atoms and
25 man made ones.
They can all
be found
on the
periodic
table.
Everything about you and everything around you is
made of these atoms or combinations or mixtures of
these atoms.
For example:
Water (H2O)
2 hydrogen atoms
& 1 oxygen atom
Salt (NaCl)
1 sodium atom &
1 chlorine atom
Properties of Matter
Physical Property - a quality or condition of matter that
can be observed or measured without changing the
arrangement of atoms that make it
Examples:
•Mass
• color
•Length
• size
•Volume
• shape
•Boiling point
• state of matter
•Melting point
• texture
These properties can usually be observed using our
senses or measured with equipment in the lab.
Chemical Properties – property that can only
be observed when the arrangement of
particles that make the matter are altered
These properties usually tell you how a
substance will react in the presence of a
second substance.
Examples:
Iron reacts with oxygen to form rust.
Metals react with acids to form hydrogen
gas.
Changes in Matter
Physical Changes – changes in matter that do not
alter the arrangement of atoms that make the
matter
Changes in size, shape, and STATE OF MATTER.
Examples:
crumpling up a piece of paper
breaking a stick in half
melting ice
salt dissolving in water
Chemical Changes - changes in matter that DO
alter the arrangement of atoms that make
the matter
Because you can’t see the particles to
determine if arrangement has changes, you
can look for clues that tell you a chemical
change has occurred.
Clues of a Chemical Change:
1. color change
2. production of a solid
3. production of a gas
4. release of heat, light, or sparks
Conservation Laws
Law of Conservation of Matter
Matter is neither created or destroyed
In reaction =
Amounts of reactants = amount of products made
Law of Conservation of Energy
Energy is neither created or destroyed BUT
is rater it is transformed from one form to
another
Identify the following as either a physical property
or a chemical property.
Property
Physical
a shirt is red
√
sodium is so soft it can be
cut with a knife
√
Chemical
potassium reacts vigorously
with water
√
paper is flammable
√
water boils at 100 oC
√
Identify the following as either a physical change or
a chemical change.
Change
Physical
Chemical
√
burning toast
breaking a glass
√
melting butter
√
leaves changing color
√
fireworks exploding
√
Intensive vs. Extensive

Intensive properties are properties unique
to a pure substance. It is a property that
can be used to identify it.
Ex: Density, boiling point, melting point, odor, hardness

Extensive properties are properties that
many kinds of substances can have and will
not identify the substance.
Ex: Mass, volume, shape
Now that we can describe matter,
we can begin to classify it
Matter-anything with mass and volume
Matter is separated into two categories: pure
substances and mixtures.
Matter
Mixtures
Pure
Substance
Pure Substance – a substance made of the
same kind of atoms or compounds having a
unique set of chemical and physical
properties
The two categories of pure substances are
elements and compounds
Pure Substance
Element
Compound
Element




simplest type of pure substance
made of only 1 kind of atom
Examples:
Hydrogen (H2)
Diatomic
molecules are still
Oxygen (O2)
elements.
H. BrONClIF
Carbon (C)
all particles are identical
cannot be separated by a physical or a
chemical change
Compounds
 made of two or more different kinds of
elements chemically combined together
in a specific ratio
Examples:
H2O - Water
H2O2 - Hydrogen
Peroxide
NH3 - Ammonia
NaHCO3 – Baking soda

elements in a compound can only be
broken apart by a chemical change
Classify the following as either an
element or a compound.
Mixtures
physical blend of two or more pure
substances.
 can be separated by a physical change
The two categories of mixtures are
homogeneous and heterogeneous.

Mixtures
Homogeneous
Mixtures
Heterogeneous
Mixtures
Homogeneous Mixtures
 mixtures that are uniform in composition on the
atomic level.
 all parts of the mixture have the same
concentration of matter.
 Different parts of the mixture can not be
identified (transparent appearance for solutions)
 Alloys: solution of metal
 also called a solution
Examples:
Salt water, vinegar
Lemonade, alcohol
3% H2O2 and H2O solution
Steel, solder or 14 K gold
Tyndall Effect

If you shine a flashlight through a
jar of a translucent colloid, the
particles scatter the light, making
the beam visible.
Ex. Fog is an example
of a colloid.
This is why you
can see headlights
on a foggy day.
19

You can use the Tyndall effect to
see if your mixture is
heterogeneous or homogeneous

If you can see
the beam its
heterogeneous, if
you can’t it is a
true solution or
homogeneous
20
Heterogeneous Mixtures
 mixtures that are not uniform in
composition
 all parts of the mixture are not the same
 the different parts can usually be easily
identified from one another
Examples:
rocks and sand
salt and pepper
oil and water
Pizza
Colloids

Colloid are formed of
clusters of atoms or
molecules. The particles
are larger than the solvent
molecules in a true
solution.
Ex. mayonnaise, egg whites and
gelatin which never separate
upon standing and do not
qualify as true solutions.
22
Suspensions

Suspensions are mixtures that
settle upon standing. Suspensions
can be separated by filtering.
Ex. Dirt and debris in lake water.
All the mud is at
the bottom of
the bucket.
23
Classify the following as either a
homogeneous mixture or a
heterogeneous mixture.
Classify the following everyday
common objects as a homogeneous
mixture or a heterogeneous mixture.
Jelly
Soda
Pizza
Mixed Nuts
Lotion
Chunky Peanut Butter
Matter
Pure Substances
Element
Compound
Mixtures
Homogeneous
Heterogeneous
State of Matter- Matter can be solid, liquid,
gas or plasma depending on how much kinetic
energy (or motion) they have.



Solid: Particles vibrate in place. It has a definite
volume and a definite shape.
Liquid: Particles roll around each other. It has a
definite volume but no definite shape.
Gas: Particles move around colliding with one
another. It has no definite volume or shape.


Vapor is liquid or solid at room temperature
Plasma: Particles are so hot and excited that the
electrons leave the nucleus and matter is ionized or
charged
Matter in Motion
The Kinetic Molecular Theory states
that atoms and molecules are always
in motion.
Remember, the temperature of a substance
is the measure of its kinetic energy.

That energy can only do one thing at a time:
1. Change the state of the substance.
2. Increase the temperature of a substance.
1. Changes in the states of Matter
Boiling
Condensing
Freezing
Melting
Sublimating
Depositing
2. Heating Curve
This curve can also work
in reverse if energy is
being taken away.


Absolute
Zero is the
temperature at
which all
motion of
particles stops.
Scientists have
yet to reach it.
Separating Mixtures
Mixtures
are physical blends of two or
more pure substances.
Since
they are mixed physically, they can
be separated into the individual pure
substances by physical changes.
Compare and Contrast the two types of mixtures.
•all parts are
the same
•different parts
of the mixture
can not be
identified from
one another
•physical blend
of two or more
pure substances
•can be
separated by
physical
changes
•It is
transparent
(unless it is an
alloy or mixture
of metals)


Contrast
Compare
•all parts are
not the same
•the different
parts of the
mixture can
usually be
easily
identified or it
is opaque or
translucent

Contrast
Methods of Separating Mixtures
using: Freezing and Boiling Example: Separate
Points
alcohol and water
Distillation - method of separating components of a solution
using their boiling points.
•
involves 3 stages and both are state of matter changes
(1) The solution is boiled to
vaporize one component
of the solution with the
lower boiling point.
(2) As soon as the temperature
starts to rise, the vapor
stops being collected since
this rise in temperature
indicates the end of a phase
change.
(3) The vapor is cooled to
turn it back into a liquid
Solubility
1.
2.
3.
Example: Separate sand and salt.
Dissolve substance that is soluble in
water.
Filtration - uses a filter of porous material
to separate a mixture of liquid and
insoluble components
Evaporate the liquid portion of a solution
which changes to a gas or vapor leaving a
solid behind
Magnetism - used to separate components of a
mixture when one is attracted to a magnet and
one is not
Chromatography - method of separation used to
see what colors make up an ink or substance
containing different molecules.
Steps of Chromatography
1. Material to be separated
is spotted on
chromatography paper
2. Paper is dipped into a
solution that will be
absorbed by the paper
and moves up
3. Some colors move more
than others and separate