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Pure
Substances
and Mixtures Chapter 1: Classifying
Matter
1.1 What is
Matter? Key
Question: What is matter made of
and how does it behave?
What Is Matter?
• Matter is anything that takes up space and has mass. For
example, chocolate, water, wood, steel and air.
• The study of matter and its changes is called chemistry, and
those who work in this area are called chemists.
• The particle theory of matter states that all matter is made up
of tiny particles that are always moving randomly, that attract
each other, and that have empty space between them.
• The particles move faster and farther apart when they are
heated.
• The particles themselves do not look like the kind of matter
they make up. For example, a particle of water does not look
or behave like the water in a lake.
matter
chemistry
particle theory of
matter
1.1
1.1 What is Matter? Matter is anything that takes up space and has mass.
• All objects around you are made up of matter
(e.g. the air and your body).
• The study of matter and its changes are called
chemistry.
• Chemistry is the study of matter and its changes.
• Chemists can often imitate, or copy the matter
found in nature using artificial chemicals.
• Artificial chemicals can be good for people (e.g., some medicines are made up of matter in plants)
• Artificial chemicals can be used to make
medicines cost less. The medicines with these chemicals are often purer than the medicines
made from plants.
• Not all artificial chemicals are better though
(e.g., lemonade made from lemons has vitamin
C. Lemonade made with artificial flavours does
not have as much vitamin C.
The Makeup of Matter • All matter is made up of very tiny particles. You
can see these particles only with a very strong
microscope. These particles do not always look
like the matter they make up.
The Particle Theory of
Matter Scientists use the particle theory of matter (a.k.a.
“particle theory”
• There are 5 aspects to “The Particle Theory”
Particle Theory
1) All matter is made up of tiny particles
2) Particles have empty spaces between them
3) Even though you cannot see them, particles
are moving randomly all the time.
4) Particles move faster and spread farther
apart when they are heated.
5) Particles attract each other, so they tend to
stay together rater then fly apart.
1.2 More About
Matter
Key Questions: What are the three states of
matter?
More About Matter
• All forms of matter, including water, can exist in three different
states: solid, liquid, and gas.
• A solid has a definite shape and a definite volume.
• A liquid has a definite volume, but does not have a definite
shape. It takes the shape of its container.
• A gas does not have a definite volume or a definite shape. It
takes the volume and shape of its container.
• The particles of a sample of matter always stay the same,
whether the matter is solid, liquid, or gas. The difference is in
the movement and arrangement of the particles.
• Matter can change state when a sample is heated or cooled.
solid
volume
liquid
gas
1.2
Three States of Matter
All forms of matter can exist in three
different states:
1) Solid
2) Liquid
3) Gas
Solids
Solid is a state of matter with a definite
volume and a definite shape.
Volume is a measure of the quantity of
space occupied by an object. It is how
much space something takes up.
Its shape and volume stay the same.
Liquids
Liquid is a state of matter with a definite
volume, but no definite shape; a liquid
takes the shape of its container.
Example: Water is a liquid. If you have 150
mL of water in a glass, the water’s volume
is 150 mL. If you pour the water into a
bowl, the volume is still 150 mL. However,
the water’s shape will change.
Gases
Gas is a state of matter that does not
have a definite volume or a definite
shape; a gas takes the shape and volume
of its containers.
When a balloon is filled with air, the air
particles take the shape of a sphere. The
volume of the air particles inside the
balloon is equal to the volume of the
balloon.
Particles of Solids, Liquids, and
Gases The particles of a sample of matter always stay the same in
all three states of matter.
The difference between solids, liquids, and gases is in : 1) The movement of particles 2) The arrangement of particles Link: This link is a rap about the states of matter. http://www.youtube.com/watch?v=cBBmdqti_Kg
Link: This link will show you how a liquid and gas move in their states. http://members.shaw.ca/r.burak/Ch07/ch7_kmt_solids_liquids_gases.html
Particle
movement
Particle
arrangement
Illustration
Solids Stay in the
same
position but
move, or
rotate, a little
Very close
together
Liquids Move around
in all
directions
Close
together
Gases Have lots of
energy and
move very
quickly in all
directions
Far apart
Particle Attraction Particles of matter attract each other
When particles are close together, forces of attraction hold the particles together.
The volume of liquids and solids does not change much because the particles are close together.
When particles are far apart, the forces of attraction cannot hold the particles together.
The volume of gases changes because the particles are far apart.
Changes in State Matter can change from one state to another. A
change in state can happen when matter is heated or cooled.
Ice changes to water when it is heated. The heat causes the water particles to move faster and spread apart to become a liquid. More heat makes the water change to a gas.
If a gas is cooled, the particles move slower. The gas changes into a liquid. If cooled further, the liquid may freeze into a solid.
When matter changes state, the particles stay the same. The number of particles also stays the same. Only the arrangement and movement of the particles change.
1.4 Pure
Substances
and Mixtures
Key Question: What makes a substance
pure? What makes a
substance a mixture?
Pure Substances and Mixtures
• A pure substance is a type of matter that contains only one
kind of particle. For example, aluminum, table sugar, and
distilled water are pure substances.
• A mixture is a type of matter that contains two or more pure
substances mixed together. For example, steel, salt water,
milk, and air are mixtures.
• Mixtures can be solids, liquids, or gases, or even
combinations of these.
1.4
pure substance
mixture
Pure Substances
Pure substances is a substance made of
one type of particle.
Example: white sugar is a pure substance.
White table sugar contains only sugar
particles. All of the sugar particles have
the same structure.
Pure substances include: aluminum foil,
table salt, distilled water.
Pure Substances
Distilled water is different from tap water.
Tap water is not a pure substance. Tap
water has other particles in it. Some of
these substances come from the pipes.
Distilled water does not have these other
substances.
Mixtures Some substances look pure. They seem like
they are made up of one kind of particle. They are really made of many different particles.
Example: cow’s milk. Cow’s milk might seem like a pure substance. It is actually a mixture!
A mixture is made of two or more pure substances mixed together.
Some substances in cow’s milk are: water, lactose, fat, protein, minerals and vitamins
Making Mixtures
Think of a glass of distilled water. It is a
pure substance. You add sugar to
sweeten the water. Sugar is another pure
substance. The sweetened water is a
mixture of distilled water and sugar.
Making Mixtures
There are many kinds of mixtures. Here are
some familiar mixtures:
1) Steel
2) Batteries
3) Juice
4) Air
5) Concrete
Making Mixtures Mixtures can contain pure substances that are
dangerous. Batteries and certain light bulbs contain harmful substances.
Mercury and lead are two examples of dangerous pure substances.
It is important to separate and recycle these dangerous parts. They should not be placed with regular garbage.
They should be brought to special recycling stations.
Knowing about pure substances and mixtures will help you dispose of chemicals properly.
1.6 Mechanical
Mixtures and
Solutions
Key Question: What is the difference
between a mechanical
mixture and a solution?
• Scientists classify mixtures
into two main groups:
mechanical mixtures and
solutions.
• If you can see different kinds of matter in a mixture, it is
called a mechanical mixture (or a heterogeneous mixture).
For example soil, chocolate chip cookies, and granola bars
are mechanical mixtures.
• Mixtures that look as though they are pure substances are
called solutions (or homogeneous mixtures). For example,
apple juice, seawater, and air are solutions.
• The different particles of a solution
are evenly mixed. The different
particles of a mechanical mixture
are unevenly mixed.
Mechanical Mixtures and Solutions 1.6
mechanical mixture
heterogeneous mixture
solution
homogeneous mixture
Comparing Mixtures
Making food involves many mixtures.
Example: an omelette could be a mixture
of eggs, vegetables, and cheese.
Mixtures are made of two or more
different kinds of particles. Scientists put
mixtures into two groups:
1) Mechanical Mixtures
2) Solutions
1. Mechanical Mixtures
It is not always easy to tell if something is a
mixture. You might not always be able to
see the different parts.
Mechanical mixture is one where you can
see the different parts of the mixture.
Mechanical mixtures are also called
heterogeneous mixtures.
Mechanical Mixtures
You can use mechanical mixtures every
day. You can find a mechanical mixture:
1) Inside your closet
2) Inside your pencil case
3) On your dinner plate
4) On the playground
Mechanical Mixtures
They can exist anywhere. You know soil is
a mechanical mixture because you can
see the different parts. Soil might have:
sand, gravel, twigs, and leaves.
Mechanical Mixtures
Other mechanical mixtures are not as
easy to see.
Imagine you have a mixture of sugar and
salt. Since sugar and salt look alike, it may
look like one substance.
If you look closely, you can see the
different crystals.
2. Solutions Some mixtures look like pure substances.
Example: grape juice looks like one substance. So does shampoo. However they are both mixtures.
Mixtures that look like pure substances are called solutions.
Solutions have more than one kind of particle, but they look like pure substances.
Solutions can also be called homogeneous mixtures.
Solutions
Some solutions you know are:
1) Steel
2) Seawater
3) Milk
4) air
Solutions
Solutions can be in any three states: solid,
liquid, or gas. For example:
Solution State Parts
Candle wax Solid Wax (paraffin or
beeswax), sent
oils
Air Gas Nitrogen,
oxygen, argon,
other gases
Blood Liquid Platelets, red
blood cells,
white blood
cells, water
Solutions Do you know why you cannot see the
different parts of a solution?
Particles in a solution are mixed together evenly. You cannot see the individual particles. This makes the solution look like one substance.
Particles in a mechanical mixture are not mixed evenly. The particles stay together in groups. You can see these groups as different kinds of matter.
Solutions
Solution Mechanical
Mixture
Classifying Matter
You know that matter can be grouped as:
1) A pure substance
2) A mixture
Mixtures can be grouped as:
1) Mechanical mixtures
2) Solutions
Summarizes what you already
know: Matter
Can combine to form
Pure substances Mixtures
Mechanical
mixtures Solutions
Classification of Matter
Scientific
Method Scientific Method Process
Scientific Method Link: These are raps to help you remember the
scientific method.
http://www.youtube.com/watch?v=bUa-ilQqEv0
http://www.youtube.com/watch?v=8Xg4bIpuvRw
Link: This is the scientific method in action with the Big Bang Theory
http://www.youtube.com/watch?v=_7sSuhQ1_24
Summary – Looking Back
Human production, use, and disposal of pure substances and mixtures
have both benefits and costs.
• We use pure substances and mixtures in everything we do.
• Some mixtures contain pure substances that are harmful to people and
the environment.
• Some pure substances are beneficial but are also potentially dangerous.
The particle theory explains the behaviour of particles of matter.
• Everything that has mass and takes up space is made of matter.
• The particle theory states that all matter is made up of tiny particles that are
separated by empty spaces. These particles are attracted to one another.
• The particle theory states that particles are
in constant motion, and move faster and
farther apart when they are heated.
• Three states of matter are solid, liquid,
and gas.
CHAPTER
1
Summary – Looking Back
The skills of analysis can be used to apply the particle theory to changes
in matter.
• Changes in mass observed during investigations can be explained using
the particle theory.
A pure substance contains only one kind of particle, but a mixture
contains more than one kind of particle.
• Aluminum, table sugar, salt, and distilled water are all examples of
pure substances.
• The particles of pure substances do not change, regardless of their
state of matter.
• Mixtures can be mechanical mixtures
(heterogeneous mixtures) or solutions
(homogeneous mixtures).
• Chocolate chip cookies, steel, salad
dressing, pop, and ketchup are examples
of mixtures.
CHAPTER
1
Summary – Looking Back
The skills of scientific inquiry can be used to classify matter as a pure
substance or a mixture.
• Pure substances and mixtures can be identified using observation skills.
• Different properties of pure substances and mixtures can be determined
by mixing them together.
A mechanical mixture contains different components that you can see.
• A granola bar, cooking oil with herbs, and a children’s ball room are all
examples of mechanical mixtures.
• A mechanical mixture is also called a heterogeneous mixture.
A solution is a mixture that looks like a pure substance.
• Stainless steel, clear tea, and clear nail polish are all solutions.
• A solution is also called a homogeneous mixture.
CHAPTER
1
