Kinetic Theory

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Kinetic Theory Solids
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Kinetic Theory and Solids Vocabulary

• Temperature
• Kinetic Energy
• Kinetic Theory
• Gas pressure
• Vacuum
• Atmospheric pressure
• Barometer
• Pascal (Pa)

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Kinetic Theory and Solids Vocabulary

• Standard atmosphere (atm)
• Celsius scale
• Kelvin scale
• Absolute temperature, p74
• Crystal
• Hydrated crystal
• Anhydrous crystal
• Boiling

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Kinetic Theory and Solids Vocabulary

• Amorphous solid
• Unit cell
• Thermometer
• Hygroscopic
• Absolute zero
• Efflorescent
• Deliquescent

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Kinetic Theory and Solids Vocabulary

• Water of hydration
• Boiling point
• Normal boiling point
• Melting point

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Objective 1 Kinetic Molecular Theory

• All matter is composed of small particles (atoms,
  ions, molecules)
• These particles are in constant motion
• All collisions between particles are perfectly
  elastic

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Objective 2 Factors affecting number of
collisions

• Temperature
• Known as the average kinetic energy of the
  particles
• Increasing Temp, increases number of collisions
  of the particles
• Temp of collisions are directly proportional

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Objective 2 Factors affecting number of
collisions

• Volume
• Increasing volume decreases the number of
  collisions
• Volume and collisions are inversely proportional

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Objective 2 Factors affecting number of
collisions

• Number of particles
• Increasing the number of particles, increases the
  number of collisions
• particles is directly proportional to the
  number of collisions

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Objective 3 Pressure

• Pressure Force/Area
• Gas Pressure depends on the number of
  collisions with the inside wall of the container.
• Atmospheric pressure (air pressure) results
  from the collisions of air molecules with the
  outside of objects.
• Vacuum no particles present therefore no
  pressure.

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Objective 4 Units of pressure

• Standard Units of Pressure (at sea level)
• mmHg millimeter of Mercury
• Atm atmosphere
• kPa kiloPascals (SI unit of pressure)
• 760mmHg 1.00atm 101.3kPa 760 torr
• Pressure conversions using dimensional analysis
• 190.mmHg ? ?atm
• 34.5kPa ? ?mmHg
• 1.30atm ? ?kPa

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Objective 5 Measuring Pressure

• Barometer a device used to measure air pressure
• Increasing air pressure moves the mercury up the
  column.
• The height of the mercury is proportional to
• the air pressure.

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Objective 5 Measuring Pressure

• Aneroid barometer has a closed sealed capsule
  with flexible sides. Any change in pressure
  alters the thickness of the capsule. Levers
  magnify these changes, causing a pointer to move
  on a dial.
• (aneroid without fluid).

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Objective 10 Temperature Scales
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Objective 10 Temperature Scales

• The Celsius temperature scale is based on melting
  boiling point of water
• The Kelvin scale is based on absolute zero.
• At 0 K all motions ceases because the Kinetic
  Energy of the particles reaches zero.
• Known as the absolute temperature scale because
  zero is lowest temperature (no negative Temp)
• 0 K -273.15oC
• Temperature increments on the Kelvin and Celsius
  scale are the same distance apart.

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Temperature Scales

• Temperature Conversions
• oC 273 K
• oC K _273
• Practice Calculations
• 25 oC ? ? K
• 86K ? ? oC

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Objective 7 Kinetic Energy

• The energy an object possesses because of its
  motion

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Objective 8

• Kinetic Energy ½ (mass)(velocity)2
• KE ½ mv2
• At a given temperature, particles with a small
  mass will move faster than particles with a
  larger mass.
• Mass is inversely proportional to the velocity

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Objective 11 Temperature

• Temperature a measure of the average kinetic
  energy of the particles in a substance
• If two substances have the same temperature, they
  have the same K.E. regardless of the number of
  particles present.
• Increase Temperature, increases K.E.
• Decrease Temperature, decreases K.E.
• Temperature and K.E. are directly proportional.

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Objective 910

• Diffusion the tendency of molecules and ions to
  move toward areas of lower concentration until
  the concentration is evenly mixed.
• All gases do not diffuse at the same rate. Rate
  depends on the mass of the particles.
• Grahams Law the rate of effusion or diffusion
  is inversely proportional to the square root of
  its formula mass.

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Objective 14 Heat flow

• Heat energy flows from warmer objects to cooler
  objects

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States of Matter
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SOLIDS

• Particles are packed together in a highly
  organized pattern.
• Tend to be dense and incompressible
• Vibrational motion (increases as temperature
  increases)

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Crystal

• A substance in which the particles are arranged
  in an orderly, repeating, 3-D pattern called a
  crystal lattice.
• The type of bonding that exists between the atoms
  determines the melting point of the crystal.
• The size and arrangement of particles determines
  the crystal shape.
• Breaks along cleavage planes

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Unit Cell

• The smallest group of particles within a crystal
  that retains the shape of the crystal.
• 14 types
• Determine the overall shape of a crystal

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Amorphous solids

• Noncrystalline solids
• Lack an ordered internal structure (not crystals)
• Atoms are arranged randomly
• Identified by a lack of melting point and random
  breaking patterns.
• Often called supercooled liquids.
• Ex. Glass, wax, plastic

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Network Solids

• Solids in which all atoms are covalently bonded
  to each other.
• Very high melting points and extremely hard.
• Ex. Diamonds and silicon carbide

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Hydrated Crystals

• Crystals with water as an integral part of the
  crystal.
• Water must be present to have the crystal shape
• Does not feel wet
• Ex. CoCl2 6H2O pink crystal
• CoCl2 blue powder

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Anhydrous Crystals

• Hydrated crystals that have lost their water of
  hydration (CoCl2 blue powder)
• Can be formed by gently heating hydrated
  compounds and evaporating the water. Mass is
  less after heating.

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Efflorescent

• Hydrated crystals that lose their water of
  hydration to the air when humidity (water vapor
  pressure) is low.

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Hygroscopic

• Crystals that absorb water from the air to form
  hydrated crystals. (not all do this)
• Can be used as drying agents called dessicants.
• ex. Silica gel packets found in electronics,
  shoes, etc.
• Deliquescent compounds absorb so much water from
  the air they dissolve and form solutions.

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Hygroscopic Compounds continued

• Can be recognized because the become heavier if
  allowed to sit out in the air.