Chapter 13 – States of Matter
Chem 311 Period 3
•Kinetic Energy: the energy an object has because of its motion
•Kinetic Theory:
•All matter consists of tiny particles in CONSTANT MOTION•PARTICLES IN GAS are small, hard sphere w/ insignificant volume
•Particles are relatively far apart (compared to those of solids / liquids)•Particles are NOT attracted or repulsed by each other•Motion of one particle of gas INDEPENDENT of motion of other particles
THUS Motion of particles of Gas: Rapid, constant, random (unaffected by each other)
• As a result, gases can spread out into space w/o limit (any shape)
travel in straight paths until they collide with another particle or object - they change direction only when they rebound/collide with another particle or
object.•All collisions between particles in a gas are perfectly elastic
• Elastic collision: Kinetic energy is transferred WITHOUT LOSS from one particle to another – total kinetic energy remains CONSTANT
Measuring Air Pressure
A Barometer is a device used to measure atmospheric pressure and can be read the same way as a thermometer.
The height of the mercury in a barometer depends on weather and altitude. The higher the altitude, the lower the pressure.
The atmospheric pressure pushes the mercury from the reservoir into the glass tube. The pressure at sea level is 760mm, or 29.2 inches. The tip of the tube is a vacuum- an empty space with no pressure or particles.
Gas Pressure
Gas Pressure is the result of simultaneous collisions of billions of rapidly moving gas particles against an object. The more collisions, the higher the pressure.
The collision / movement of these gas particles can be explained with the Kinetic theory (which states that matter consists of tiny particles in constant motion).
The Pascal (Pa) is the SI unit of pressure, another unit of measurement is millimeters of mercury (mm Hg) and standard atmospheres (atm).
Kinetic Theory + Distribution Curve
Increase in kinetic energy= increase in temperature
Higher temperature has wider range of kinetic energies
Increase in avg kinetic energy causes a rise of the temperature
Kelvin
At absolute zero (0 K) particles have no kinetic energy/no motion. There is no lower temperature than absolute zero Kelvin.
Kelvin temperature is directly proportional to the avg kinetic energy of a substance For example, particles
of helium at 200K have 2x the avg kinetic energy as helium at 100K
A Model for Liquids
Both the particles in gases and the particles in liquids have kinetic energy.
This energy allows the particles in gases and liquids to flow past each other.
Substances that can flow are known as fluids.
Since fluids flow the way they do, they conform to the shape of their containers.
Pt. II Unlike the particles of gases, inter-molecular attractions
reduce the amount of space between the particles in liquids.
Since the particles of liquids are close together, liquids have a definite volume.
Liquids are consequently much more dense than gases Changing the amount of pressure on a liquid hardly
effects its volume. Since liquids and solids are mostly incondensable, they
are known as condensed states of matter.
5) Vaporization with kinetic theory
Vaporization=liquid converted to a vapor or gas
Kinetic Theory- all matter consists tiny particles in constant motion
Most molecules do not have high enough kinetic energy (movement of particles) to overcome attractive force & vaporize
5) Vaporization with kinetic theory
Molecules above a certain point of high kinetic energy (rapid motion) can vaporize
Molecules evaporate from surface of liquid to a gas
5)Manometer
Measures equilibrium vapor pressure when mercury levels in tubes fluctuate
Liquid added, pressure increases-moving mercury in U-Tube
Difference in levels of mercury = vapor pressure in mm of Hg.
6) Boiling Point
Boiling occurs – liquid heated to temp where particles have high enough kinetic energy to vaporize
Heating water creates higher level kinetic energy (rapid motion molecules).
Boiling point- temp high enough for vapor pressure of liquid to equal the external pressure pushing on liquid
Solid Organization and PropertiesSolid Organization and Properties Closely packed ions, atoms, or Closely packed ions, atoms, or
molecules, well organizedmolecules, well organized Particles have fixed location and vibrate Particles have fixed location and vibrate
around fixed points, strong attractionsaround fixed points, strong attractions Solids do not flowSolids do not flow
Dense (not easily compressed)Dense (not easily compressed) Melting pointsMelting points
Ionic solids- high melting pointIonic solids- high melting point Molecular solids- low melting pointMolecular solids- low melting point
Melting Point of SolidsMelting Point of Solids
melting point-melting point-temperature where solid changes temperature where solid changes into a liquidinto a liquid When melted, solid particles have high When melted, solid particles have high
vibrations that allow them to move out of vibrations that allow them to move out of fixed positions and into liquid formfixed positions and into liquid form
Equilibrium- Equilibrium- temperature where melting temperature where melting point of solid and freezing point of liquid are point of solid and freezing point of liquid are at same temperatureat same temperature
Melting point is determined by particle Melting point is determined by particle organizationorganization
Solid melting point exceptionsSolid melting point exceptions Cane sugar and woodCane sugar and wood
Crystal Structures and SystemsCrystal Structures and Systems
Crystal-Crystal- three dimensional pattern arrangement of three dimensional pattern arrangement of solid particlessolid particles
Crystal shape describes solid particle arrangementCrystal shape describes solid particle arrangement Crystal propertiesCrystal properties
Has sides or faceHas sides or face Labeled a, b, cLabeled a, b, c
Has angles that intersect at facesHas angles that intersect at faces Labeled β, Υ, αLabeled β, Υ, α
Seven groups of crystals- cubic, tetragonal, Seven groups of crystals- cubic, tetragonal, rhombic, monoclinic, triclinic, hexagonal, and rhombic, monoclinic, triclinic, hexagonal, and rhombohedrarhombohedra
Liquid Organization and PropertiesLiquid Organization and Properties Contain kinetic energyContain kinetic energy Fluids-Fluids- particles that flow particles that flow
Allows liquids to take shape of containerAllows liquids to take shape of container Particles have relatively strong attractionsParticles have relatively strong attractions
Keep particles togetherKeep particles together Create definite volumeCreate definite volume Keeps particles close togetherKeeps particles close together
Denser than gases, less dense then solidsDenser than gases, less dense then solids Not effected by pressureNot effected by pressure
Gas Organization and PropertiesGas Organization and Properties
Particles have kinetic energy (like liquids)Particles have kinetic energy (like liquids) Keeps particles in constant motionKeeps particles in constant motion
Particles are small hard spheres with Particles are small hard spheres with insignificant volumeinsignificant volume Spacing is highSpacing is high No attractive forces to hold them togetherNo attractive forces to hold them together
Particles are in constant motionParticles are in constant motion Fill container regardless of shapeFill container regardless of shape
Attractive forces
Organization of particles
Gases No Particles in constant motion
Liquids Yes, slightly strong
Takes shape of container
Solids Yes, very strong
In crystal structures
Solid Liquid Gas Organization and Solid Liquid Gas Organization and AttractionAttraction
Distinguishing Between Crystal and Distinguishing Between Crystal and GlassGlass
Properties of CrystalProperties of Crystal Particles are arranged in an orderly, 3-D pattern called a Particles are arranged in an orderly, 3-D pattern called a
crystal latticecrystal lattice Has sides, or facesHas sides, or faces In general, have high melting points (unless molecular)In general, have high melting points (unless molecular) When shattered, fragments have the same surface angles When shattered, fragments have the same surface angles
as the original solidas the original solid Properties of GlassProperties of Glass
Also called amorphous solidAlso called amorphous solid Crystallization does not occurCrystallization does not occur The structures of glasses are intermediate between those of The structures of glasses are intermediate between those of
crystalline and those of free-flowing liquidscrystalline and those of free-flowing liquids Do not melt at a definite temp.Do not melt at a definite temp. When shattered, fragments have irregular angles and When shattered, fragments have irregular angles and
jagged edgesjagged edges
Crystal vs. Glass StructuresCrystal vs. Glass Structures
CrystalCrystal The shape of a crystal reflects The shape of a crystal reflects
the arrangement of particles the arrangement of particles within the solidwithin the solid
The smallest group of particles The smallest group of particles that retains its geometric shape that retains its geometric shape is the unit cellis the unit cell The unit cell may be simple cubic, The unit cell may be simple cubic,
body-centered cubic, or face-body-centered cubic, or face-centered cubiccentered cubic
GlassGlass Glasses or, amorphous solids, Glasses or, amorphous solids,
are transparent fusion products are transparent fusion products of inorganic substances that of inorganic substances that have cooled to a rigid state have cooled to a rigid state WITHOUT crystallizingWITHOUT crystallizing
Different Shapes of Crystal SystemsDifferent Shapes of Crystal Systems
Sublimation
When a solid becomes a gas without passes through the liquid state.
Occurs when a solid has a vapor pressure higher than the pressure at or near room temperature.
Vapor pressure: the measure of a force exerted by a gas above a liquid (true for solids too)
Deposition
When a gas becomes a solid without passes through the liquid state.
Phase diagram-shows the conditions and pressure at which a
substance exists as a solid, liquid, and gas
Triple point- the only set of conditions where all three states can exist.
Critical point- beyond this region the physical and chemical properties of water and steam converge to the point where they are identical. Thus, beyond the critical point, we refer to this single phase as a "supercritical fluid".
Boiling, melting, and subliming curves
Plasma: What is it?
Most common state of matter Electrically charged particles at high energy that
collect around electromagnetic fields and form gas-like clouds
It is made of extremely hot ions and electrons in space, but on Earth, it cools into atoms and molecules
The particles are affected by electromagnetic, electric, and magnetic signals but are hardly affected by gravity.
Plasma: What is it? (cont.)
The full range of plasma’s density, temperature, and spatial scales is nearly incomprehensible as it is so wide and varied.
Without sufficient energy, the plasma reverts back to a neutral gas
Energy being thermal, electrical, or light (i.e. ultraviolet)
Ions and electrons move independently in large spaces
Plasmas are still being studied and understood today
Plasma Examples
Flames neon signs Nebulae (Clouds in space) solar wind Auroras Galaxies dense solid state of matter Stars Space Lightning florescent lights