kinetic-molecular theory
based on the idea that particles of matter are always in motion
ideal gas
a hypothetical gas that perfectly fits all the assumption of the kinetic-molecular theory
elastic collision
one in which there is no net loss of total kinetic energy
kinetic energy
energy of motion
real gas
At a gas that does not behave completely according to the assumptions of the kinetic-molecular the
diffusion
such spontaneous mixing of the particles of two substances cause by their random motion
effusion
a gas that does not behave completely according to the assumptions of the kinetic-molecular theory.
fluid
a substance that can flow and therefore take the shape of its container
surface tension
a force that tends to pull adjacent parts of liquids surface together, thereby decreasing surface are to the smallest possible size
capillary action
the attraction of the surface of a liquid to the surface of a solid
freezing
the physical change of a liquid to a solid by removal of energy as heat
evaporation
the process by which particles escape from the surface of a nonboiling liquid and enter the gas state.
vaporization
the process by which a liquid or solid changes to a gas
crystalline solids
they consist of crystals
crystal
a substance in which the particles are arranged in an orderly, geometric, repeating pattern
amorphous solids
ones in which the particles are arranged randomly
supercooled liquids
substances that retain certain liquid properties even at temperatures at which they appear to be solid.
melting point
the temperature at which a solid becomes a liquid
melting
the physical change of a solid to a liquid by the addition of energy as heat.
unit cell
the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice
crystal structure
the total three-dimensional arrangement of particles of a crystal
phase
any part of a system that has uniform composition and properties
condensation
the process by which a gas changes to a liquid
equilibrium
a dynamic condition in which two opposing changes occur at equal rates in a closed system
equilibrium vapor pressure
the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature
volatile liquids
liquids that evaporate readily
equilibrium vapor pressure
the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature
boiling point
the temperature at which the equilibrium vapor pressure of the liquid equals the atmospheric pressure.
boiling
the conversion of a liquid to a vapor within the liquid as well as at its surface
molar enthalpy of vaporization
the amount of energy as heat that is needed to vaporize one mole of liquid at the liquid's boiling point at constant pressure
normal freezing point
the temperature at which the solid and liquid are in equilibrium at 1 atm
molar enthalpy of fusion
the amount of energy as heat required to melt one mole of solid at the solid's melting point
phase diagram
a graph of pressure versus temperature that shows the condition under which the phases of substance exist
sublimation
the change of state from a solid directly to a gas
deposition
the change of state from a gas directly to solid
triple point
the temperature and pressure conditions at which the solid, liquid, and vapor of the substance can coexist at equilibrium
critical point
the critical temperature and critical pressure
critical temperature
the temperature above which the substance cannot exist in the liquid state
critical pressure
the lowest pressure at which the substance can exist as a liquid at the critical temperature