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absolute zero
|
temperature at which the volume of a gas would be zero according to Charles’s law.
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Amontons’s law
|
(also, Gay-Lussac’s law) pressure of a given number of moles of gas is directly proportional to its kelvin temperature when the volume is held constant
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atmosphere (atm)
|
unit of pressure; 1 atm = 101,325 Pa
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Avogadro’s law
|
volume of a gas at constant temperature and pressure is proportional to the number of gas molecules
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bar
|
(bar or b) unit of pressure; 1 bar = 100,000 Pa
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barometer
|
device used to measure atmospheric pressure
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Boyle’s law
|
volume of a given number of moles of gas held at constant temperature is inversely proportional to the pressure under which it is measured
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Charles’s law
|
volume of a given number of moles of gas is directly proportional to its kelvin temperature when the pressure is held constant
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compressibility factor (Z)
|
ratio of the experimentally measured molar volume for a gas to its molar volume as computed from the ideal gas equation
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Dalton’s law of partial pressures
|
total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the component gases
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diffusion
|
movement of an atom or molecule from a region of relatively high concentration to one of relatively low concentration (discussed in this chapter with regard to gaseous species, but applicable to species in any phase)
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effusion
|
transfer of gaseous atoms or molecules from a container to a vacuum through very small openings
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Graham’s law of effusion
|
rates of diffusion and effusion of gases are inversely proportional to the square roots of their molecular masses
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hydrostatic pressure
|
pressure exerted by a fluid due to gravity
|
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ideal gas
|
hypothetical gas whose physical properties are perfectly described by the gas laws
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ideal gas constant (
R
)
|
constant derived from the ideal gas equation
R
= 0.08206 L atm mol
–1
K
–1
or 8.314 L kPa mol
–1
K
–1
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ideal gas law
|
relation between the pressure, volume, amount, and temperature of a gas under conditions derived by combination of the simple gas laws
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kinetic molecular theory
|
theory based on simple principles and assumptions that effectively explains ideal gas behavior
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manometer
|
device used to measure the pressure of a gas trapped in a container
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mean free path
|
average distance a molecule travels between collisions
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mole fraction (
X
)
|
concentration unit defined as the ratio of the molar amount of a mixture component to the total number of moles of all mixture components
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|
partial pressure
|
pressure exerted by an individual gas in a mixture
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pascal (Pa)
|
SI unit of pressure; 1 Pa = 1 N/m
2
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pounds per square inch (psi)
|
unit of pressure common in the US
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pressure
|
force exerted per unit area
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rate of diffusion
|
amount of gas diffusing through a given area over a given time
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root mean square speed (
u
rms
)
|
measure of average speed for a group of particles calculated as the square root of the average squared speed
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standard conditions of temperature and pressure (STP)
|
273.15 K (0 °C) and 1 atm (101.325 kPa)
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standard molar volume
|
volume of 1 mole of gas at STP, approximately 22.4 L for gases behaving ideally
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torr
|
unit of pressure;
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van der Waals equation
|
modified version of the ideal gas equation containing additional terms to account for non-ideal gas behavior
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vapor pressure of water
|
pressure exerted by water vapor in equilibrium with liquid water in a closed container at a specific temperature
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