Chapter Two

1
Chapter Two

• Solids, Liquids, and Gases

2
Lesson 2-1- States of Matter

• Although there is an new state of matter
  Plasma, for this chapter, we are going to talk
  about three states of matter
• Liquid
• Solid
• Gas

3
Solids

• A solid has a definite volume and a definite
  shape.
• The particles that make up a solid are tightly
  packed. Each particle is tightly fixed in one
  position making them hard to move.
• Particles in a solid are not completely
  motionless, the particles vibrate.

4
Solid/Molecules
5
Solids

• In many solids, particles form a regular,
  repeating pattern. These patterns are called
  crystals.
• Solids that are made up of crystals are called
  crystalline solids sugar and salt.

6
Solids

• Amphorous Solids, for example rubber and plastic,
  are not arranged in a sequenced pattern.

7
Liquids

• Liquid has no shape of its own.
• A liquid takes on the shape of its container.
• The particles in a liquid are packed almost as
  closely as in a solid, however, the particles
  have room to move freely.
• A liquid has definite volume.

8
Liquids

• Because the particles in a liquid are free to
  move, a liquid can flow from place to place.
• Some liquids flow more easily than others the
  resistance of a liquid to flow is called
  viscosity.
• Liquids with high viscosity move slow, and
  liquids with low viscosity move fast.

9
Test Yourself

• Liquid Breakfast
• Orange Juice Maple Syrup
• Which has high viscosity? Which has low viscosity?

10
Test Yourself

• Orange Juice --- Low Viscosity
• Maple Syrup --- High Viscosity

11
Gases

• A gas does not have definite shape or definite
  volume.
• A gas can change volume very easily.
• The particles of a gas move at high speeds in all
  directions.
• Gas particles spread apart, filling all the space
  available to them.

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SOLID
LIQUID
GAS
13
Lesson Two

• Gas Behavior

14
2-2

• The volume of gas is the volume of its container.
• Temperature is a measure of the average energy of
  motion of particles of a substance.
• The faster the particles are moving, the greater
  their energy, and the higher the temperature.

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2-2

• Because gas particles are moving, they are
  constantly colliding with one another.
• They also bump along the walls of their
  container.
• As a result, the gas exerts an outward push on
  the walls of the container. Pressure of the gas
  is the force of its outward push divided by the
  area of the walls of the container.

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2-2 Measuring Pressure

• Pressure is measured in units of kilopascals
  (kPa).
• Pressure Force
• 
  Area

17
2-2 Robert Boyles Law

• The relationship between the pressure and volume
  of a gas is named Boyles Law.
• When the pressure of a gas is increased at a
  constant temperature, the volume of the gas
  decreases. When the pressure is decreased, the
  volume increases.

18
Boyles Law Animation

• http//www.chem.iastate.edu/group/Greenbowe/sectio
  ns/projectfolder/flashfiles/gaslaw/boyles_law_grap
  h.html

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Boyles Law

• http//www.grc.nasa.gov/WWW/K-12/airplane/aboyle.h
  tml

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Boyles Law
21
2-2 Boyles Law

• Truck Tires
• The truck is empty and waiting at the loading
  dock
• The truck is then loaded with a delivery of 20
  refrigerators
• (1) Is there more pressure on the tires with the
  
• loaded delivery compared to the empty
  truck?
• (2) Does the delivery increase the volume of air
  in the tires, or decrease the volume of air in
  the tires?

22
2-2 Charless Law

• The relationship between temperature and volume
  of gas is named Charless Law.
• Charles found that when the temperature of a gas
  is increased at constant pressure, its volume
  increases. When the temperature of a gas is
  decreased, its volume decreases.

23
Charles Law - Animation

• http//www.chem.iastate.edu/group/Greenbowe/sectio
  ns/projectfolder/flashfiles/gaslaw/charles_law.htm
  l

24
2-2 Charless Law

• (1)You fill a helium balloon on a winter day
  does the volume of the balloon expand or
  contract?
• (2) You fill a helium balloon on a summer day
  does the volume of the balloon expand or
  contract?

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2-2 Charless Law

• Winter Day the cold temperatures help the
  balloon to expand.
• Summer Day the hotter temperatures make the
  balloon contract.

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2-2 Test Yourself

1. Does air in a sealed balloon placed in the a
   freezer represent Boyles or Charless Law?
2. Does a hippity-hop represent Boyles or Charless
   Law? Explain.

27
Lesson 2-4

• Changes in State

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2-4 Thermal Energy

• Every substance contains energy from the movement
  of its particles, called thermal energy.
• Thermal energy is transferred from one substance
  to another as heat.
• Thermal energy always flows from a warmer
  substance to a cooler substance.
• A substance changes state when its thermal energy
  increases or decreases by a sufficient amount.

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2-4 Melting

• The change in state from a solid to a liquid.

• Solid
• (Snow)
• Liquid

Snow melts Into a puddle
30
2-4 Freezing

• The change of state from liquid to solid the
  reverse of melting.
• You fill an ice-cube tray with water. You put
  the tray into the freezer and wait two hours.
  The tray is filled with ice cubes.

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2-4 Vaporization

• Vaporization occurs when a liquid gains enough
  energy to become a gas.
• Liquid to Gas Boiling Point.

• A pot of boiling water left on the stove will
  cause the liquid to vaporize into steam until the
  water is gone.

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2-4 Evaporation

• Some confuse evaporation and vaporization.
  Evaporation occurs below a liquids boiling point
  - occurring on a liquids surface. Vaporization
  occurs when a liquid reaches its boiling point.

• The rain causes puddles to occur. The sun comes
  out and the puddles soon evaporate into the
  clouds, and the cycle begins again.

33
2-4 Condensation

• The opposite of vaporization. Condensation
  occurs when a gas loses enough thermal energy to
  become a liquid.

• On hot summer day, you set your glass of lemonade
  on the porch. Before you know it, your glass is
  sweating beads of water droplets. Condensation.

34
Condensation
35
2-4 Sublimation

• Sublimation occurs when the surface particles of
  a solid gain enough energy to become a gas. In
  sublimation, particles do not pass through the
  liquid state.

36
Sublimation

• Evaporation is not quite the correct term to
  describe what happens to a comet as it approaches
  the sun. The correct term is sublimation. The
  term describes what happens when a frozen
  material changes to gaseous form. (Evaporation
  describes what happens when a liquid changes to a
  vapor).
• The most common example of sublimation is that of
  dry ice, which is the common name of frozen CO2.
  When dry ice is exposed to the air it begins to
  sublimate, or change to vapor, before your very
  eyes. This happens to dry ice because at room
  temperature the frozen gas would rather be a gas
  than frozen solid.

37

• When a comet approaches the sun, the comet comes
  to a region of space where it is warm enough that
  the frozen gases inside the nucleus would rather
  be gaseous than frozen solid, and that is when
  the tail and coma of the comet form.