MATTER and ENERGY
Pages 70-78
1. All matter is made up of atoms and molecules that act as tiny particles.
2. These tiny particles are always in motion.
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State of matter depends on its molecular motion as measured by
temperature.
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As the temperature goes up, the motion of the particles goes up
-
As the temperature goes down, the motion of the particles goes
down.
3. At the same temperature, the heavier particles move slower than the lighter
particles.
TEMPERATURE
• A measure of the average kinetic energy in a sample.
STATES OF MATTER
There are 4 states of matter
• Solids
• Liquids
• Gasses
• Plasma
We classify what a substance is based on the following
• how particles are arranged
• how much energy particles have
• the distance that exists between particles
SOLIDS
• Particles of solids are tightly packed, vibrating around a fixed position.
• Solids have a definite shape and definite volume.
Examples
• Diamonds
• Salt
LIQUIDS
• Particles of liquids are lightly packed, but are far enough apart to slide over
one another.
• Liquids have an indefinite shape and a definite volume.
• Liquids take the shape of whatever container they are in, but they cannot
be squeezed into a smaller volume.
Examples
• Mercury
• Water
GASES
• Particles of gases are very far apart and move freely.
• Gases have an indefinite shape and indefinite volume
• Since particles are not close together, the can be squeezed
into a smaller space.
Examples
• Neon
• Chlorine
PLASMA
• A plasma is a gas-like mixture of charged particles.
• Plasma is a very good conductor of electricity
Ex. Fluorescent lights, stars
• Plasma, like gases, have an indefinite shape and an indefinite volume
• Plasma is the most common state of matter in the universe.
The classification and properties of matter depend upon microscopic
structure.
• Particle arrangement
• Particle energy
• Particle to particle distance
PHASE CHANGES
• Melting/freezing
• Boiling (vaporization)/ Condensing
• Sublimation
• Evaporation
MELTING/FREEZING POINT
• Change from solid to liquid and liquid to solid
• Occurs at same temperature.
• If melting, particles are gaining energy
• If freezing, particles are loosing energy
• During the phase change, the temp. remains constant.
• After all the sample has changed phase, the temp will change
BOILING/CONDESATION POINT (VAPORIZATION)
• Change from liquid to gas and gas to liquid.
• Occurs at the same temperature
• If boiling, particles are gaining energy
• If condensing, particles are losing energy
• During the phase change, the temperature remains constant
• After all the sample has changed phase, the temperature will change.
• During the phase change, potential energy is changing, but KE is constant
EVAPORATION
• Liquid changes to a gas, but not necessarily at the boiling point
temperature.
• Some particles gain enough KE to overcome the attractive force and
become a gas.
SUBLIMATION
• Changing directly from a solid to a gas.
• Changing directly from a gas to a solid.
• The liquid state is skipped
Examples
• Dry Ice
• Mothballs