Transcript Chapters 2-3 Notes (powepoint)

CHEMISTRY
MATTER
AND
STATES OF MATTER
Hold on to your hats!
It’s going to be an exciting ride!
CHEMISTRY
• The study of the composition, structure, and
properties of matter and the changes that
matter undergoes
• Includes: chemical and physical properties,
how things interact, and what they are made
of.
WHAT IS MATTER
• Matter – Anything that has mass and takes
up space
• Composition of Matter:
–
–
–
–
Atoms
Elements
Molecules
Compounds
Composition of Matter
• Element (Pure Substance) – A substance that cannot be
broken down into simpler substances by chemical
means
– Examples: Oxygen, Aluminum, Carbon
– Located in the periodic table
• Names of Elements
– The first 103 elements have internationally accepted
names, which are derived from:
• The compound or substance in which the element was
discovered
• An unusual or identifying property of the element
• Places, cities, and countries
• Famous scientists
• Greek mythology
• Astronomical objects.
1A
8A
2A
3A
8B
3B
4B
5B
6B
7B
1B
2B
4A
5A
6A
7A
• The elements of aluminum, Iron, Oxygen, and Silicon make
up about 88 percent of the earth's solid surface. Water on the
surface and in the air as clouds and fog is made up of
hydrogen and oxygen. The air is 99 percent nitrogen and
oxygen. Hydrogen, oxygen, and carbon make up 97 percent
of a person. Thus almost everything you see in this picture
us made up of just six elements.
Composition of Matter
• Atoms – The smallest unit of an element
that maintains the properties of that element
– The particles that make up all matter
Composition of Matter
• Compounds – A substance made of two
or more different elements that are
chemically combined
– Example: Nylon is a combination of
carbon, hydrogen, nitrogen,and oxygen
atoms
– Example: Composition of air
• Compounds have unique properties
different from the elements themselves
– Example: Sodium is very reactive (reacts with
water violently)
– Example: Chlorine is a very toxic gas (has been
used as chemical warfare gas)
– Sodium and Chlorine combined make TABLE
SALT…the properties change when elements
become compounds.
Sodium and Chlorine
= Table Salt
Composition of Matter
• Molecule – The smallest unit of a substance
that keeps all of the physical and chemical
properties of that substance.
– Example: one water molecule carries all the
properties of a glass full of water
Chemical Formula
• A combination of chemical symbols and
numbers to represent a substance
– Shows the number of atoms of each element in
a compound
– Ex: Table Sugar
C12H22O11
– 12 Carbon atoms, 22 Hydrogen atoms, 11
Oxygen atoms
Substances and Mixtures
• A pure substance is a kind of matter that
cannot be separated into other kinds of
matter by any physical process.
– Pure Substances are Elements or compounds
• A mixture is a material that can be
separated by physical means into two or
more substances.
– Homogeneous or Heterogeneous
Pure Substances and Mixtures Chart

Get two types of mixtures:
– A homogeneous mixture is a mixture that
is uniform in its properties throughout
given samples.
–Often called a SOLUTION
– A heterogeneous mixture is a mixture that
consists of physicallly distinct parts, each
with different properties.
Heterogeneous
Homogeneous
2 Types Heterogeneous Mixtures
• 1. Suspension – particles can separate out
– EX: Orange juice with pulp
• 2. Colloid – particles are able to separate
light and cannot be separated by ordinary
filters.
– EX: milk, Jello, fog
Figure 3.4: Table salt is stirred into water (left), forming a
homogeneous mixture called a solution (right)
Figure 3.5: Sand and water do not mix to form a
uniform mixture
Separation of Mixtures
Examples to separate homogeneous mixtures:
- Distillation
- Chromatography
Examples to separate heterogeneous mixtures:
- Magnetic
- Filtration
• Sugar (A) is a compound that can be easily
decomposed to simpler substances by heating. (B)
One of the simpler substances is the black element
carbon, which cannot be further decomposed by
chemical or physical means.
Basic Distillation Setup
Separation of Mixtures by Paper
Chromatography
Figure 3.9: Separation of a sand-saltwater mixture
States of Matter
Classifications of Matter
Solid  rigid, definite volume and shape.
Liquid  relatively incompressible fluid,
definite volume, takes shape of
container.
Gas  easily compressible fluid, no fixed
volume or shape.
Total disorder
Lots of empty space
Gas
Disorder
Some space
Particles closer
together
Liquid
Order
Particles fixed
in position
Solid
Plasma
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•
•
•
•
•
Fourth state of matter
Most common in the universe
Does not have a definite shape
Particles can conduct electric current
Electric and magnetic fields affect plasma
Natural plasma is found in lightning, fire,
and aurora borealis
Energy and Changes in State
An introduction through music…
Kinetic Theory of Matter
• All matter is made of atoms and molecules
that act like tiny particles
• All of these tiny particles are in
MOTION.
• The higher the temperature, the faster the
particles move.
• Heavy particles move slower than light
particles at the same temperature.
Thermal Energy and Expansion
• Most matter expands when it gets hot and
contracts when it cools (exception: water)
• Thermal Energy – The total kinetic energy
of the particles that make up the object.
– Objects with a lot of kinetic energy have more
thermal energy
• Temperature is a measure of average kinetic
energy.
– Objects with more motion in their particles will
have a higher temperature
Expansion Joints
Changes of State
• Evaporation and Condensation
• Freezing and Melting
• Sublimation and Deposition
State Changes
• Evaporation – Liquid changes to a gas
– Water to steam
• sweating
• Condensation – Gas changes to a liquid
– Steam to water
• Water droplets on the side of your glass
•Heat of Vaporization – the
amount of energy needed to
change a material from a
liquid to a gas
• Melting – Solid changes to a liquid
– Ice to water
• Heat of Fusion – the amount of energy
needed to change a material from the solid
state to the liquid state
• Freezing – Liquid changes to a solid
– Water to ice
• Sublimation – Solid changes to a gas
skipping the liquid state
– Dry ice
• Deposition – Gas changes to a solid
skipping the liquid state
Transfer of Heat Energy
• Heat energy always moves from the warmer
object to the colder object.
• Caused by the Kinetic Theory of Matter
• Three Ways:
– Conduction
– Convection
– Radiation
Conduction
• The transfer of heat energy by touch
– Ex: touching the desk will transfer heat energy
from your hand to the desk.
Convection
• The transfer of heat energy by motion of
particles.
• The warmer particles rise and push colder
particles down…the cycle continues and
causes a current.
– Ex: boiling water
Radiation
• The transfer of heat through light.
Properties of Matter
Physical and Chemical
Physical Properties
• Physical Property – any characteristic of a
material that you can observe without
changing the substances that make up the
material
– Easily observed and measurable
– Includes: Shape, size, color, mass, volume,
density, temperature, melting point, boiling
point, state of matter
Chemical Property
• A characteristic of a substance that indicates
it can change chemically
– Not as easy to observe
– Includes: flammability, reactivity
– Example: Steel combined with oxygen can lead
to rust
Physical Changes

A physical change is a change in the form of
matter but not in its chemical identity.
Example:
- Dissolution of salt.
- Distillation
- Breaking pencil in two
- Cutting hair
• Physical changes help to separate
mixtures.
Chemical Changes


A chemical change or chemical reaction is
a change in which one or more kinds of
matter are transformed into a new kind of
matter or several new kinds of matter.
Cannot be reversed by physical changes
Example:
- The rusting of iron.
- Digesting food
- Rotting fruit
- Rusting steel
- Burning gasoline
Chemical Changes (cont)
• Chemical changes can be detected by such
things as odor or color
• Chemical changes form new substances that
have new properties
– Example: baking a cake
Law of Conservation of Mass
• Matter is not created or destroyed during a
chemical change
• The mass of all substances before a
chemical change equals the mass of all
substances after the chemical change