Chapter 2
Introduction to matter
8th Grade Science
Properties of Matter
• ____________is
anything that takes up space
Matter
and has mass.
Chemistry
• _____________is
the study of the properties
of matter and how matter changes
properties
• The ____________
and changes in matter
depend on its makeup or composition
substance
• A __________is
a single type of matter that is
pure (has a specific set of properties)Examples
of pure substances:_________________
Sugar and salt
Properties of Matter
• Every form of matter has two kinds of properties:
Physical properties – characteristics of a pure
– ________
substance that can be observed without changing it
into another substance. A physical property of water
is that it freezes at 0
• Solid, liquid, gas are physical properties of matter
– _________
Chemical properties – a characteristic of a pure
substance that describes its ability to change into
different substances. To observe the chemical
properties you must try to change it to another
substance. Flammability, reactivity,
Examples of physical and chemical
properties
• Physical
– Freezing
– Bumpy texture and color are physical properties
– Flexibility – bend into shapes without breaking
Chemical
- Iron forms rust when it is combined with oxygen in air
- Silver will react with sulfur in air to form tarnish
- Property of gold is that it does not react easily with
oxygen and sulfur
Elements
• An ______________is
a pure substance that
element
cannot be broken down into any other substance
by chemical or physical means.
– Simplest substances
Physical
– Identified by specific __________and
Chemical
______________properties
Aluminum
– Examples: ______________(foil)
and
Copper
___________(pennies)
– Elements can be in solid, liquid or gas form
– Elements are represented by either one or two-letter
Al
C (carbon)
symbols such as ___(aluminum)
or __
Particles of Elements
• An ____________is
the basic particle from
Atom
which elements are made
– Different elements have different properties
atoms
because their _________
are different.
– All matter is made up of _____________
atoms
– Atoms have the ability to combine with
other atoms
___________.
– When atoms combine they form a ____________Chemical bond
a force of attraction between two atoms.
When Atoms Combine…..
• Atoms combine to form larger particles called
___________.
molecules
• Molecules are groups of two or more atoms
held together by ________________.
Chemical bonds
• Water – two atoms of _________
Hydrogen (H) chemically
bonded to one atom of _________.
Oxygen (O)
• Two atoms of the same element can combine
to form a _______.
molecule
Compounds
• All ______is
made up of _______
matter
elements
• Most _________in
nature are found combined
elements
with other _________.
elements
• A pure substance made up of two or more
elements chemically combined in a set ratio is
called a ___________
compound
Chemical formula
• A compound is represented by ____________
• The chemical formula show the elements that are
found in the compound and the ratio of the
______
atoms Ex. Carbon dioxide- ratio 1:2
Chemical Formulas
• If a different ratio of carbon to oxygen was
present – it would be a different___________.
compound
• When elements are chemically combined,
they form compounds having ________that
properties
are different from those of the uncombined
elements.
• Examples:
– silver sulfide
– Table sugar
Mixtures
• Elements and compounds are _____________
Pure substances
• A __________
is made up of two or more
mixture
substances – the substances can be elements,
compounds, or both.
• Mixtures differ from compounds in two ways:
– Each substance in a mixture keeps
its____________________
Individual properties
Set ratio
– Parts of a mixture are not combined in a_________.
Example: soil mixture, sand, clay, water, etc. Not all soil
samples are the same
Types of Mixtures
• ________________
- a mixture where you can
heterogeneous
see the individual parts. Example: salad
homogeneous
• ________________
- substances are evenly
mixed so that the individual substances
cannot be seen. Example: lemonade
solution
– ______________
is an example of a homogeneous
mixture.
• Does not have to be a liquid
• Air is an example of a solution-gas solution
• Brass is an example of a solid solution
Separating Mixtures
• A _________
Compound is difficult to separate into its
elements
• A ________
is not difficult to separate into its
Mixture
components because each component keeps its
properties
own _____________.
• Methods of separating a mixture:
–
–
–
–
Magnetic attraction
Filtering the mixture
Distilling a liquid solution
evaporation
Measuring Matter
Weight
___________
is a measure of the force of gravity on an
object.
- on Earth, all objects are attracted towards the center
of the earth based on the force of the earth’s gravity.
On the moon, you would weigh one sixth of your total
weight on earth.
Mass
____________
is the measurement of the amount of
matter in an object
-the mass of your body does not change on the moon
* Weight can change with location. Mass does not
change with location even when the force of gravity on
the object changes.
Units of Mass, Volume, and Density
• ______________________is
the
International System of Units (SI)
measurement system used by scientists to
measure properties of matter.
Volume
• ____________is
the amount of space that
matter occupies. Formula: length x width x
height
Density
• ____________relates
to the mass of a
material in a given volume. Formula: mass ÷
volume
Sinking or Floating
greater
• Objects with densities ________than
water
will sink.
less
• Objects with densities _________than
that of
water will float.
physical
• Density is a ___________property
of a
substance.
• Brainpower – why does the oil in a bottle of
salad dressing rise to the top of the bottle?
Section 2 Assessment
• Question 1a and 1b
• Question 2a, 2b, and 2c
• Question 4 Calculating Density Practice
Changes in Matter
Physical
• _______________
change is any change that
alters the form or appearance of matter but
does not make any substance in the matter
into a different substance.
– Example: sand that is used in an art sculpture is
still sand just in a different form
– When matter changes state from a solid, liquid, or
physical
gas – a _____________change
has occurred.
Examples of Physical Changes
•
•
•
•
•
•
•
Dissolving
_____________
_____________
Bending
____________
Crushing
Breaking
_____________
____________
Chopping
_____________
Filtration
Distillation
_____________
Chemical Change
• _____________
change is a change in matter
Chemical
that produces one or more new substances
- a substance is transformed into a different
substance.
properties
- the new substances have ___________
that
are different from the original substances
- Examples of chemical changes: burning
natural gas, rust, tarnish, and breaking down
water into its elements
Examples of Chemical Change
Chemical Change
Description
Example
Combustion
A rapid reaction between
fuel and oxygen that
results in fire
Gas, oil, or coal burning in
a furnace
Electrolysis
Use of electricity to break a Breaking down water into
compound into its
oxygen and hydrogen
elements or simpler
compounds
Oxidation
Slow combination of a
substance with oxygen
Rusting of an iron fence
Tarnishing
Slow combination of a
bright metal with sulfur or
another substance,
producing a dark coating
on the metal
Tarnishing of brass
Law of Conservation of Mass
• __________________in
the 1770’s made
Antoine Lavoisier
accurate measurements of mass both before and
after a chemical change.
• His data showed that mass was neither lost nor
gained as a result of the change
Law of Conservation of Mass - matter is not created
• _____________________
or destroyed
matter
– Since mass measures the amount of _________,
this
law is sometimes referred to as the
Law of Conservation of Matter
__________________________
Conserving Matter
Chemical Reaction in Methane
• No mass is lost during the combustion of
methane gas
• During a chemical change, ________
are not
atoms
lost or gained – they are simply rearranged.
methane
• For every molecule of ________
that burns,
two molecules of _________
are used.
oxygen
• The ______are
rearranged in the reaction, but
atoms
they do not disappear.
Thermal Energy
Energy
• ____________is
the ability to do work or cause change
• Chemical or physical changes in _________
includes a
matter
Energy
change in __________.
• ______________
is a measure of the average energy or
Temperature
random motion of particles of matter
Thermal Energy is the total energy of the particles in
• ______________
an object
Temperature
• __________________is
related to the amount of
__________________
an object has.
Thermal Energy
• ___________________
always flows from warmer
Thermal Energy
matter to cooler matter
Thermal Energy and Changes in Matter
• When matter changes thermal energy is either
absorbed
__________
or ____________
released
Endothermic
• ______________
change is a change in which
energy is taken in
• _______________
change occurs when
Exothermic
energy is released or given off
Combustion
• ___________
is a chemical change that
releases energy in the form of heat and light
Forms of Energy
• Energy comes in many forms:
– Kinetic
– Potential
– Chemical
– Electromagnetic
– Electrical
– Thermal
Kinetic Energy
• Kinetic Energy – the energy of matter in
motion
_________.
kinetic
– The smallest particles of matter have __________
energy because they are in constant, random
motion.
– The kinetic energy of particles contributes to the
thermal
__________
energy of a substance
– A rolling ball has kinetic energy because the
particles that make up the ball are in motion.
Potential Energy
stored
• Potential energy is energy that is ________
as
a result of the objects _________.
position
– When a diver climbs to the top of a diving board
increases
his/her potential energy ___________.
– When you stretch a rubber band, you are giving
potential
the rubber band ____________
energy because it
has the ability to snap back and do work.
– Other types of potential energy: a book on top of
your desk – it has the potential to fall off
Chemical Energy
• Chemical energy is the internal energy stored
Chemical bonds
in the _______________
between atoms.
• Chemical energy is also a form of potential
_______
energy because the energy is stored.
• When a chemical change occurs, the chemical
bonds are broken
_______ and new bonds are
formed.
Electromagnetic energy
• Electromagnetic energy is a form of energy
waves
that travels through _________
as ________.
space
• Examples: radio waves, infrared rays, the
waves that heat food in the microwave,
ultraviolet waves, and x-rays.
• _________
Visible light is an example of electromagnetic
energy.
• __________
changes give off electromagnetic
Chemical
energy such as light from a wood fire.
Electrical Energy
• Electrical Energy is the energy of
________charged
particles moving from one
electrically
place to another.
electrons
• ___________
move from one atom to another
in many ____________
reactions.
Chemical
• _____________
are two metal strips that are
Electrodes
used to conduct electrical energy when
connected to an electrical energy source such
battery
as a ____________.
Transformed Energy
• Burning of fuel is a ________
chemical change that
Chemical
transforms ____________
energy and releases it
thermal
electromagnetic
as ____________
energy and ____________
energy.
• When you exercise, ___________
energy from
chemical
kinetic
food is transformed into __________
energy of
your moving muscles.
• Photosynthesis – plants transform ____________
electromagnetic
energy into _________
energy as they make
chemical
molecules of sugar.
Section 2-4 Assessment
• 1a, 1b, 2a, 2b, 2c