Solids and Liquids

melting = change of a solid to the liquid (fusion)

freezing = change of a liquid to the solid state

vaporization = change of a solid or a liquid to the vapor

sublimation = change of a solid directly to the vapor

condensation = change of a gas to the liquid state

depostition = chande of a vapor to a solid

liquefaction = change of a substance that is normally a gas to the liquid state

vapor pressure = partial pressure of the vapor over the liquid (measured at equilibrium

equilibrium = state in which the rates of two opposing molecular processes (vaproization and condensation)

volatile = describes liquids and solids with relatively high vapor pressures at normal temperatures (alcohols)

boiling point = temperature at which the vapor pressure of a liquid equals the atmospheric pressure

normal boiling point = temperature at which the vapor pressure of a liquid equals 1 atm

heat of fusion = enthalpy change for the melting of a solid

heat of vaproization = enthalpy change for the vaporization of a liquid

phase diagram = graph that summarizes the conditions of temperature and pressure under which the three states of a substance are stable

triple point = point on a phase diagram representing the temperature and pressure at which a solid, liquid, and a gas can exist in equilibrium

critiacal point = the point where the vapor pressure curve ends and at which no matter the temperature and pressure no liquid state can exixt

surface tension = cohesive forces holding together a substance ex:  the beading of water droplets

capillary action = adhesive forces holding a substance to another substance (meniscus)

viscocity = resistance to flow exhibited by all liquids

intermolecular forces = attractive forces between molecules

dipole-dipole = attractive IMF resulting from a polar molecule: 2nd strongest van der Walls force

London dispersion force = weakest attractive force between non polar molecules and polar molecules

hydrogen bonding = strongest IMF between polar H to N or polar H to O, or polar H to F bonds

unit cell = smallest unit from which we can imagine creating a crystal by repeating it in three dimensions

allotrope = different forms of the same element

amorphous solid = solid that lack crystal structure (glass)

crystal = true solid with well defined regular shape

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