States of matter

Common states of matter on Earth Solid Definite shape and volume Liquid Definite volume but not shape Gas No definite shape or volume

Other states of matter Plasma Bose-Einstein Condensate exists at extremely high temperatures Makes up 99% of the matter in the universe, but is nearly nonexistent on Earth Bose-Einstein Condensate

Kinetic Theory Kinetic Theory: all particles of matter are in constant motion Kinetic energy: the energy that comes from an object’s motion. KE = ½ mv2

Intermolecular forces There are attractive forces between all the particles of matter In gases, particles move so quickly these forces can be ignored In liquids, the particles have enough kinetic energy to change the shape, but the forces keep a constant volume In solids, the particles simply vibrate in place, held tight by the forces

Phase changes

Melting and Freezing Melting is sometimes called fusion The quantity of heat required to fully melt a certain mass of a substance is called the heat of fusion The heat of fusion of water is 334 Joules per gram

Vaporization Vaporization: either boiling or evaporating Boiling occurs when vapor pressure equals atmospheric pressure Vapor pressure: pressure that comes from the gases above the liquid The quantity of energy required to completely boil a certain mass of liquid is called heat of vaporization Heat of vaporization of water is 2261 Joules per gram

Phase Changes Phase change: reversible, physical change Temperature does not change during a phase change

Heating curve for water

Exothermic and endothermic phase changes Endothermic changes absorb heat In order for molecules to speed up and break formation, they must grab heat from their surroundings Exothermic changes release heat In order for molecules to slow down, they must dump heat into their surroundings

Exothermic or Endothermic phase change? Freezing………….. Melting……………. Vaporization……… Condensation……. Sublimation……… Deposition………..

Gas Laws

Pressure Pressure is the result of a force distributed over an area In a gas, pressure comes from collisions between particles and the wall of the container

Units of Pressure Newtons per square meter (N/m²) One N/m² is called a pascal (Pa) We often use kilopascals (kPa, 1kPa = 1000 Pa) Standard atmosphere (atm) 1 atm = 101,325 Pa or 101.325 kPa

Factors that affect gas pressure Number of particles Increasing the number of particles of gas will increase its pressure if volume and temperature are constant Temperature Increasing the temperature of a gas will increase its pressure if the number of particles and volume are constant Volume Decreasing the volume of a gas will increase its pressure if the number of particles and temperature are constant

Charles’ Law Jacques Charles, 1780 Published by Joseph Louis Gay-Lussac in 1802

Charles Law Note: Temperature must be in kelvin K = ºC + 273

Absolute Zero William Thomson “Lord Kelvin”

Boyle’s Law Robert Boyle, 1662

Boyle’s Law

The Combined Gas Law Note: Temperature must be in kelvin K = ºC + 273