Matter and Change

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Chapter 1

• Matter and Change

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What is Matter?

• Matter is anything that takes up space and has
  mass.
• Mass is the amount of matter in an object.
• Mass is resistance to change in motion along a
  smooth and level surface.
• Examples

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Types of Matter

• Pure Substance- a particular kind of matter -
  pure
• Mixture- more than one kind of matter, not
  chemically combined

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What are Pure Substances?

• Substances which have a single composition
  throughout. These can be elements or compounds
• The simplest forms of matter are the elements.
  There are nearly 120 different elements currently
  known on the earth.
• The smallest particles of an element are atoms.
• Atoms of an element are unique. For example lead
  atoms are completely different from gold atoms.

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Substances

• Elements- simplest kind of matter
• Cannot be broken down into simpler
• All one kind of atom.
• Compounds are substances that can be broken down
  by chemical methods
• When they are broken down, the pieces have
  completely different properties than the
  compound. Salt
• Made of molecules- two or more atoms stuck
  together

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• A molecule is the smallest particle of a compound
  that acts as a unit. Water molecule. Molecules
  are made of a fixed ratio of atoms.

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What is a chemical formula?

• A chemical formula tells the kind and number of
  atoms in a molecule.
• The formula uses the symbols of the element to
  identify the elements present and subscripts
  (lowered numbers beside the symbol) to indicate
  how many atoms are present.

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Compound or Mixture
Compound
Mixture
One kind of piece- Molecules
More than one kind - Molecule or atoms
chemical change Required to make
physical change Can still separate parts
New substance With different properties Than the
original parts
Variable composition Parts Keep their properties
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Which is it?
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Properties

• Words that describe matter (adjectives)
• Physical Properties- a property that can be
  observed and measured without changing the
  substance.
• Chemical Properties- a property that can only be
  observed by changing the type of substance.
• Both physical and chemical properties can be used
  to help identify a substance

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Physical Properties
Color
Melting
Boiling
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Chemical Properties
Flammability
Radioactivity
Reactivity
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Properties

• Words that describe matter (adjectives)
• Extensive Properties- only depends on the amount
  of matter
• Intensive Properties- only depends on the type of
  matter, not the amount
• Both intensive and extensive properties can be
  used to help identify a substance

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Extensive Properties
Volume
Mass
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Intensive Properties
Density
Luster
Color
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Physical Changes

• A change that changes appearances, without
  changing the composition.
• Examples?
• Chemical changes - a change where a new form of
  matter is formed.
• Also called chemical reaction.
• Examples?
• Not phase changes
• Ice is still water.

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Chemical Reactions

• Another name for chemical change
• When one or more substances are changed into new
  substances.
• Reactants- stuff you start with
• Products- What you make
• NEW PROPERTIES
• Because each substance has its own properties

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Indications of a chemical reaction

• Energy absorbed or released
• Color change
• Odor change
• Precipitate- solid that separates from solution
• Not easily reversed
• Only clues not certainty

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Chemical symbols

• There are 116 elements
• Each has a 1 or two letter symbol
• First letter always capitalized second never
• Some from Latin or other languages

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Chemical symbols

• Used to write chemical formulas
• Subscripts tell us how many of each atom
• H2O
• C3H8
• HBrO3

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Conservation of Mass

• Mass can not be created or destroyed in ordinary
  (not nuclear) changes.
• All the mass can be accounted for.
• Mass at the start mass at end

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The Law of Conservation of Mass

• Matter cannot be created nor destroyed.

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Mixtures

• Made up of two substances.
• Variable composition.
• Heterogeneous- mixture is not the same from place
  to place.
• Chocolate chip cookie, gravel, soil.
• Homogeneous- same composition throughout.
• Kool-aid, air.
• Every part keeps its properties.

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What are homogeneous mixtures?

• Solutions are homogeneous mixtures. Solution
  particles are very small and compose molecules,
  atoms, or ions.
• Colloids are homogeneous mixtures. Colloid
  particles are larger than solution particles but
  do not settle as suspension do.
• Examples of colloids are fog, mayonnaise, jello,
  whipped cream.
• What is the Tyndall Effect and Brownian motion?

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What are heterogeneous mixtures?

• Heterogeneous mixtures (suspensions) are made of
  larger particles than that of homogeneous
  mixtures. These particles remain suspended
  temporarily and will eventually settle or
  separate.
• Examples are chocolate milk, orange juice, muddy
  water.

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What are liquid mixtures?

• Liquids which evenly mix are said to be miscible.
  Gasoline, antifreeze and water.
• Liquids which do not mix are said to be
  immiscible. Oil and water oil and vinegar.

Can gases mix with liquids?

• How do fish breathe?
• What are carbonated soft drinks?

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Phases

• A part of a sample with uniform composition,
  therefore uniform properties
• Homogeneous- 1 phase
• Heterogeneous more than 1

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Separating mixtures

• Only a physical change- no new matter
• Filtration- separate solids from liquids with a
  barrier
• Distillation- separate because of different
  boiling points
• Heat mixture
• Catch vapor in cooled area
• Chromatography- different substances are
  attracted to paper or gel, so move at different
  speeds

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Chromatography
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How can physical changes be used to separate
mixtures?
Impurities mixed with water can be separated by
distillation.
What is distillation? Distillation is a process
of separating parts of a mixture by differences
in boiling points.
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Solutions

• Homogeneous mixture
• Mixed molecule by molecule
• Can occur between any state of matter.
• Solid in liquid- Kool-aid
• Liquid in liquid- antifreeze
• Gas in gas- air
• Solid in solid - brass
• Liquid in gas- water vapor

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Solutions

• Like all mixtures, they keep the properties of
  the components.
• Can be separated by physical means
• Not easily separated- can be separated without
  creating anything new.

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States of matter

• Solid- matter that can not flow and has definite
  volume.
• Liquid- definite volume but takes the shape of
  its container (flows).
• Gas- a substance without definite volume or shape
  and can fl

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States of Matter
Definite Volume?
Definite Shape?
Temp. increase
Com-pressible?
Small Expans.
Solid
YES
YES
NO
Small Expans.
Liquid
NO
NO
YES
Large Expans.
Gas
NO
NO
YES
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States of Matter
Moderate Kinetic Energy - molecules move around
more than in solids
Low Kinetic Energy - molecules barely move
High Kinetic Energy molecules in rapid,
constant motion
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Liquid
Gas
Solid
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States of Matter

• There are more
• Plasma
• high temperature low pressure
• electrons separate from nucleus
• Most common in the universe
• More at very low temp
• Bose- Einstein condensate
• Quantum superfluids

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Another Way to Change States

• Pressure
• For some substances it will turn solids to
  liquids
• For others it will turn liquids to solids
• Silly putty
• Will turn gas to liquid-
• Compressor in refrigerator and AC

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Energy

• The ability to do work.
• Work - cause a change or move an object.
• Many types- all can be changed into the other.

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Types of energy

• Potential- stored energy
• Kinetic Energy- energy something has because its
  moving
• Heat- the energy that moves because of a
  temperature difference.
• Chemical energy- energy released or absorbed in a
  chemical change.
• Electrical energy - energy of moving charges

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Types of Energy

• Radiant Energy- energy that can travel through
  empty space (light, UV, infrared, radio)
• Nuclear Energy Energy from changing the nucleus
  of atoms
• All types of energy can be converted into others.
• If you trace the source far enough back, you will
  end up at nuclear energy.

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Conservation of Energy

• Energy can be neither created or destroyed in
  ordinary changes (not nuclear), it can only
  change form.
• Its not just a good idea, its the law.

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What about nuclear?

• E mc2
• energy mass x (speed of light)2
• speed of light 3 x 108
• A little mass can make a lot of energy
• Law of Conservation of Mass - Energy the total of
  the mass and energy remains the same in any change