Transcript Physical Change - St John Brebeuf

The Chemistry part of
Science 9
Section 1.2
WHAT IS CHEMISTRY ANYWAY ?!
You mean other than awesomely awesome?!
Chemistry is ...
The study of the properties, composition and
behaviour of matter…
PROPERTY VS COMPOSITION
Property is a characteristic, a trait or quality that
something has
Ex: water boils at 100 °C
Composition is what something is made up of…its
basic nature from the inside (its ingredients)
EX: water is made up of two hydrogen atoms and 1 oxygen
atom H20.
MATTER
MATTER is anything that has _____________ and
occupies ______________
Mass is the amount of ___________ in a substance or object.
Mass is often measured in grams(g) or kilograms(kg)
Volume is the amount of ______________a substance or an
object occupies.
Volume is often measured in litres (L) or mL
Ex: This bottle holds 250mL of liquid
Describing Matter
Pure Substances: a substance that is made up of only one kind of
matter. There are two kinds of pure substances:
a) Element - a pure substance that cannot be broken
down or separated into simpler substances
Ex: gold (Hg) silver(Ag)
b) Compound - a substance composed of at least two
elements
Ex: water (H20), CO2
See pages 22 - 23
HOW DO WE DESCRIBE MATTER?
We describe matter by looking at their properties
and composition.
We collect information on them. This information
can be qualitative or quantitative
Describing substances
Qualitative information is ___________________
information
 Quantitative information is __________________
information

PROPERTIES, COMPOSITION AND MATTER
Property is a characteristic, a trait or quality that
something has
Ex: water boils at 100 °C
Composition is what something is made up of…its
basic nature from the inside (its ingredients)
Ex: water is made up of two hydrogen atoms and 1 oxygen
atom H20.
PHYSICAL PROPERTIES
They are characteristics of matter that can be
observed and measured. They are either qualitative or
quantitative.
Examples: state, colour, magnetism, density, melting point,
boiling point, etc…
Different properties for different matter make them
unique and valuable.
Ex: glass is not a good conductor of heat or electricity, does not form
crystals, can easily be bent or shaped when heated…this makes it
perfect to use for window glass!!!
PHYSICAL PROPERTIES EXAMPLES:
DUCTILITY

The ability to be stretched or drawn into
wires
PHYSICAL PROPERTIES EXAMPLES:
VISCOSITY
Resistance to FLOW ! Doesn’t wanna move!
viscous = lazy

PHYSICAL PROPERTIES EXAMPLES:
MALLEABILITY
The ability to be rolled or hammered into
thin sheets
PHYSICAL PROPERTIES EXAMPLES:
DENSITY
Density: describes how tightly packed things are
together in a particular space/volume.
Density= mass
volume
Which box looks more dense??
CHEMICAL VS PHYSICAL CHANGES
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Matter can go through changes..
There are two kinds: physical and chemical
changes
How do we know which is which? !
Chemical Change
 A chemical change is a change in matter
that occurs when substances combine to form _______________
 The new substance has completely different chemical and physical
properties from what you started with.
 Ex: burning, explosions
fireworks, cooking
rusting
Chemical Change
In chemical changes, THE CHANGE IS NOT REVERSIBLE!
(NEW matter with NEW properties)
Goodbye my love, goodbye!
Physical Change (state change)
When a physical change occurs, no new substances are formed
( just the appearance changes)
-size, shape or state changes
Examples:
Cutting paper
Chopping tomatoes
Melting ice/freezing water.
Physical Changes are just changes
of State
In other words, when water turns from liquid(state)
to ice(state), it is still water with the same chemical
formula H2O.
So the chemical formula has not changed at all so the
essence is the same, only the appearance is
different!
Are the following chemical or physical
changes?
A piece of wood burns to form ash_________
Water evaporates into steam__________
A piece of wood is cut in half___________
A bicycle chain rusts ____________
Food digested in the stomach ___________
LET US CHECK OUR UNDERSTANDING
Physical and chemical changes check!

http://vital.cs.ohiou.edu/steamwebsite/downloads/
ChangeLab.swf
STATES OF MATTER

Matter can exist in three common states or
phases:_______, _______, and _______.
http://www.chem.purdue.edu/gchelp/liquids/character.html
ARE THERE OTHER STATES OF MATTER
THAT EXIST ?!
FOR YOUR INFORMATION ONLY
THERE ARE ALWAYS CHANGES OF
STATES
Things change!


Matter can change from liquid to solid, solid to
liquid, etc when energy is added or taken away…
We need to know these terms regarding those
changes
IMPORTANT POINTS WHEN STATES CHANGE


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Boiling temperature/boiling point: Temperature
at which a liquid turns into ________ .
Freezing point: Temperature at which a ______
turns into a ____________
Melting point is the temperature at which a
____________ turns into a _______________
AND SOME MORE…
Condensation: Temperature at which a _____turns
into ________
Sublimation : Temperature at which a
____________ turns into a _______________
Deposition :Temperature at which a ____________
turns into a _______________
SOMETHING TO THINK ABOUT
At what temperature does water solidify or
freeze?
At what temperature does water melt ??
MODELS TO EXPLAIN MATTER
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Scientists like to understand and explain
things…
There have been many models to explain matter
and how it behaves.
Today we will learn about a few of them …
The Particle Model of Matter
1) Describes the behaviour of matter
2) Matter is made of small particles.
There are spaces between the particles.
Gases have more space than liquids. Liquids have more space than
solids.
3) Particles are always moving.
4) Particles are attracted to each other. The
strength of attraction depends on the type of
particle.
See page 18
The Kinetic Molecular Theory
See page 19
The main points in the theory are:
1) Matter is made of small particles.
2) There is empty space between particles.
3) Particles are constantly moving.
a) Solid particles are packed together and cannot move freely. They
can only vibrate.
b) Liquid particles are farther apart and can slide past each other.
c) Gas particles are far apart and move around quickly.
4) Energy makes particles move.
The Kinetic Molecular Theory and
Changes of State
Solid
Particles are close together, fixed in position and vibrating.
Melting
As temperature increases, particles’ kinetic
energy increases.
Liquid
Particles are still close, but slide past one another.
Boiling
As temperature increases, particles’ kinetic energy
continues to increase, creating more space.
Gas
Particles are spaced out, and
highly energetic. They move freely.
See page 20
Homework
Page 27
#1,2,3,6,8.
That’s it !!! You survived your first lesson 