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Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
Matter and Energy
Chapter 2
Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
Atoms
Matter Substance that
occupies space Substance that has
mass Mass—measure of
the amount of atoms All matter is made up
of atoms Possess unique
physical and chemical properties
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Atoms (continued)
Three subatomic particles: Protons Electrons Neutrons
Protons and neutrons form the nucleus
Electrons revolve around the nucleus
Bohr model is the most popular model
Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
Atoms (continued)
Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
The Elements
Protons—subatomic particle (+) charge
Electrons—subatomic particle (–) charge
Neutron—subatomic particle with no electrical charge
Atomic number helps to classify atoms Atoms are also known as
elements Over 109 different atoms or
elements
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States of Matter
Four states: Solids – Liquids Gases – Plasma
Atoms in solids are tightly packed
Atoms in solids are restricted in movement
Atoms are in a crystal pattern
Matter in solid state has a definite shape
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Molecules of a Solid
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States of Matter (continued)
Liquids are composed of atoms that are more loosely arranged
Atoms have more freedom of movement
Liquids have no definite shape
Atoms are arranged in long chains or clumps
Movement of atoms is less restrictive
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Molecules of a Liquid
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States of Matter (continued)
When a solid turns into a liquid Refers to change in state or
phase change Phase changes depend
on certain temperature and pressure
Temperature of change: from solid to liquid called
melting point from liquid to solid called
freezing
Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
States of Matter (continued)
Atoms in a gas: Highest degree of
movement Undergo constant collisions
with other atoms Gas has no definite shape Collisions with walls of a
solid container Causes pressure More collisions the higher
the pressure
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Molecules of a Gas
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States of Matter (continued)
Liquid changes phase to a gas— vaporization
Temperature to change a liquid to a gas—boiling point
Change of a gas to a liquid—condensation
Solid directly into a gas—sublimation
Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
States of Matter (continued)
Plasma Atoms of gas are exposed to high energy Atoms begin to ionize and lose electrons This creates a high-energy fluid gas mixture
composed of ions and electrons Stars are composed of plasma
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Compounds and Molecules
109 different atoms make up Earth’s elements
Chemically joined atoms are called compounds
Compounds are referred to as molecules
More than 10 million compounds exist
Two substances mixed are called a mixture
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Energy
Relationship between matter and energy Fundamental cause for
existence Albert Einstein
Energy and mass have a mutual relationship
E = mc2
Ability to do work or cause change
Motion when matter is exposed to energy
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Energy (continued)
Two basic forms: Kinetic
Energy of motion Movement of Earth around the Sun
Potential Stored energy Gasoline in the tank of your car
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Law of the Conservation of Energy
Energy cannot be created or destroyed Energy only changes form Energy changes from one form to another
No real gain or loss Forms of energy:
mechanical – gravitational – radiant thermal – electrical –
magnetic nuclear – chemical
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Electromagnetic Radiation
Kinetic energy of movement or vibration Travels in the form of a wave
The higher the electromagnetic radiation, the shorter the wavelengths
The lower the electromagnetic radiation, the longer the wavelengths
Electromagnetic spectrum: Energy and wavelength of different forms
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Electromagnetic Radiation (continued)
Gamma rays—highest energy waves Wavelength 1 billionth of a centimeter
Radio waves—lowest energy waves Wavelength as large as 10 kilometers
Electromagnetic waves travel at the speed of light: 186,000 miles per second
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Electromagnetic Radiation (continued)
Electromagnetic energy interacts with matter: Refraction—waves change direction and bend Reflection—waves bounce off substances Scattering—waves refracted or reflected Absorbed—wave’s energy is taken in Transmission—waves pass through matter
Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
Energy Transfer
Three fundamental processes: Conduction—transfer by direct contact Radiation—movement in an empty space Convection—circular movement of heat
In gas or liquid Caused by differences in temperature & humidity
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Heat and Temperature
Temperature—substance’s average kinetic energy
Higher temperature, more motion of atoms
Temperature measured on three scales: Fahrenheit Celsius Kelvin
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Heat and Temperature (continued)
Fahrenheit and Celsius Freezing point—32°F and 0°C Boiling point—212°F and 100°C
Kelvin—measures average kinetic energy 0°K—all particles stop motion
Temperature never reached on Earth Based on absolute zero
0°K = -459.67°F and -273.16°C
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Heat and Temperature (continued)
Heat—measure of flow of kinetic energy Total kinetic energy in a system Flows from high to low kinetic energy
Called a sink Calorie = energy to raise 1 gram H2O 1°C Specific heat
Heat to raise 1 gm of a substance 1°C Also called heat capacity
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Heat and Temperature (continued)
Latent heat of condensation Water vapor to a liquid
1 gram water vapor into liquid 840 calories released
Liquid water to a solid—80 calories released Latent heat of vaporization
Liquid water vaporizes into water vapor 840 calories absorbed
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