Chapter 5 Vocab Flashcards
(26 cards)
Pressure (P)
The force exerted per unit of surface area.
Barometer
A device used to measure atmospheric pressure. Most commonly, a tube open at one end, which is filled with mercury and inverted into a dish of mercury.
Manometer
A device used to measure the pressure of a gas in a laboratory experiment.
Pascal (Pa)
The SI unit of pressure; 1 Pa = N/m2
Standard atmosphere (atm)
The average atmospheric pressure measured at seal level and 0°C, defined as 1.01325x10^5 Pa.
Millimeter of mercury (mmHg)
A unit of pressure based on the difference in the heights of mercury in a barometer or manometer. Renamed the torr in honor of Torricelli.
Torr
A unit of pressure identical to 1 mmHg.
Ideal gas
A hypothetical gas that exhibits linear relationships among volume, pressure, temperature, and amount (mol) at all conditions; approximated by simple gases at ordinary conditions.
Boyle’s law
The gas law stating that, at constant temperature and amount of gas, the volume occupied by a gas is inversely proportional to the applied (external) pressure: V ∝ 1/P.
Charles’s law
The gas law stating that, at constant pressure, the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature: V ∝ T.
Avogadro’s law
The gas law stating that, at fixed temperature and pressure, equal volumes of any ideal gas contain equal number of particles, and, therefore, the volume of the gas is directly proportional to its amount (mol): V ∝ n.
Standard temperature and pressure (STP)
The reference conditions for a gas: 0°C (273.14 K) and 1 atm (760 torr).
Standard molar volume
The volume of 1 mol of an ideal gas at standard temperature and pressure: 22.414 L.
Ideal gas law
(Also ideal gas equation) An equation that expresses the relationships among volume, pressure, temperature, and amount (mol) of an ideal gas: PV = nRT.
Universal gas constant (R)
A proportionality constant that relates the energy, amount of substance, and temperature of a system; R = 0.082057366 atm⋅L/mol⋅K = 8.3144626 J/mol⋅K.
Partial pressure
The portion of the total pressure contributed by a gas in a mixture of gases.
Mole fraction (X)
A concentration term expressed as the ratio of number of moles of solute to the total number of moles (solute plus solvent).
Kinetic-molecular theory
The model that explains macroscopic gas behavior in terms of particles in random motion whose volumes and interactions are negligible.
rms (root-mean-square) speed (urms)
The speed of a molecular having the average kinetic energy; very close to the most probable speed.
Effusion
The process by which a gas escapes from its container through a tiny hole into an evacuated space.
Diffusion
The movement of one fluid through another.
Mean free path
The average distance a particle travels between collisions at a given temperature and pressure.
Collision frequency
The average number of collisions per second that a particle undergoes.
Atmosphere
The mixture of gasses that extends from a planet’s surface and eventually merges with outer space; the gaseous region of Earth’s crust (for the unit, see standard atmosphere).
