the point on a phase diagram at which the temperature and pressure have their critical values; the end point of the liquid-vapor line
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phase diagram
Front
a convenient way of representing the phases of a substance in a closed system as a function of temperature and pressure
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superheating
Front
the process of heating a liquid above its boiling point without its boiling
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surface tension
Front
the resistance of a liquid to an increase in its surface area
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heat of vaporization
Front
the energy required to vaporize one mole of a liquid at a pressure of one atmosphere
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critical pressure
Front
the minimum pressure required to produce liquefaction of a substance at the critical temperature
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ionic solid
Front
a solid containing cations and anions at the lattice points
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critical temperature
Front
the temperature above which vapor cannot be liquefied no matter what pressure is applied
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triple point
Front
the point on a phase diagram at which all three states of a substance are present
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normal melting point
Front
the temperature at which the solid and liquid states have the same vapor pressure under conditions where the total pressure on the system is one atmosphere
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sublimation
Front
the process by which a substance goes directly from the solid to the gaseous state without passing through the liquid state
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vaporization
Front
the change in state that occurs when a liquid evaporates to form a gas; evaporization
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condensed states
Front
liquids and solids
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intermolecular forces
Front
relatively weak interactions that occur between molecules
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atomic solid
Front
a solid that contains atoms at the lattice points
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hydrogen bonding
Front
unusually strong dipole-dipole attractions that occur among molecules in which hydrogen is bonded to a highly electronegative atom such as nitrogen, oxygen, and fluorine
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normal boiling point
Front
the temperature at which the vapor pressure of a liquid is exactly one atmosphere
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equilibrium
Front
the point at which no further net change occurs in the amount of liquid or vapor because the two opposite processes exactly balance each other
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enthalpy of fusion
Front
the enthalpy change that occurs to melt a solid at its melting point
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capillary action
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the spontaneous rising of a liquid in a narrow tube
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molecular solid
Front
a solid composed of neutral molecules at the lattice points
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London dispersion forces
Front
the forces, existing among noble gas atoms and nonpolar molecules, that involve an accidental dipole that induces a momentary dipole in a neighbor
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heating curve
Front
a plot of temperature versus time for a substance where energy is added at a constant rate
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condensation
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the process by which vapor molecules reform a liquid
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equilibrium vapor pressure
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vapor pressure - the pressure of the vapor present at equilibrium
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enthalpy of vaporization
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heat of vaporization
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dipole-dipole attraction
Front
the attraction force resulting when polar molecules line up so that the positive and negative ends are close to each other
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supercooling
Front
the process of cooling a liquid below its freezing point without its changing to a solid