Chapter 12 Flashcards
Absolute zero
The zero point on the absolute temperature scale; -273.15ºC or 0ºK; theoretically, the temperature at which molecular motion is a minimum
Atmosphere (atm)
A unit of pressure; the pressure that will support a column of mercury 760 mm high at 0ºC; 760 torr
Avogadro’s Law
At the same temperature and pressure, equal volumes of all gases contain the same number of molecules
Bar
A unit of pressure; 1.00 bar is equal to 100. kPa (or 0.987 atm)
Barometer
A device for measuring atmospheric pressure. The liquid is usually mercury.
Boyle’s Law
At constant temperature, the volume occupied by a given mass of a gas is inversely proportional to the applied pressure
Charles’s Law
At constant pressure, the volume occupied by a definite mass of a gas is directly proportional to its absolute temperature
Condensed states
The solid and liquid states
Dalton’s Law of Partial Pressures
The total pressure exerted by a mixture of gases is the sum of the partial pressures of the individual gases
Diffusion
The movement of a substance (e.g., a gas) into a space or the mixing of one substance (e.g., a gas) with another
Dispersion forces
Weak, short-range attractive forces between short-lived temporary dipoles
Effusion
The escape of a gas through a tiny hole or a thin porous wall
Fluids
Substances that flow freely; gases and liquids
Gay-Lussac’s Law of Combining Volumes
At constant temperature and pressure, the volumes of reacting gases (and any gaseous products) can be expressed as ratios of small whole numbers
Ideal gas
A hypothetical gas that obeys exactly all postulates of the kinetic-molecular theory
Ideal Gas Equation
The product of the pressure and volume of an ideal gas is directly proportional to the number of moles of the gas and the absolute temperature
Kinetic-molecular theory
A theory that attempts to explain macroscopic observations on gases in microscopic or molecular terms
Manometer
A two-armed barometer
Mole fraction
The number of moles of a component of a mixture divided by the total number of moles in the mixture
Partial pressure
The pressure exerted by one gas in a mixture of gases
Pascal (Pa)
The SI unit of pressure; it is defined as the pressure exerted by a force of one newton acting on an area of one square meter
Pressure
Force per unit area
Real gases
Gases that deviate from ideal gas behavior
Root-mean-square speed, 𝓊rms
The square root of the mean-square speed, sqrt(u2). This is equal to sqrt(3RT/M) for an ideal gas. The root-mean-square speed is slightly different from the average speed, but the two quantities are proportional.
