Properties of Gases - Vocabulary Flashcards

Vocabulary flashcards covering properties of gases, kinetic theory, molar volume, density, diffusion, Graham’s law, partial pressures, Dalton’s law, atmospheric and clinical pressure measurement devices, barometric units (Torr/mmHg), hyperbaric pressure, Henry’s law, and solubility concepts.

Gas

A substance that exerts pressure, can flow, and fill available space; gases are readily compressed/expanded and diffuse.

Pressure

Force per unit area exerted by a gas on its surroundings.

Viscosity

Internal friction to flow; a property exhibited by gases (and liquids) affecting flow.

Diffusion

Spread of molecules from regions of higher concentration to lower concentration; in gases, diffusion occurs rapidly.

Kinetic energy

The internal energy of a gas largely due to molecular motion; increases with temperature.

Avogadro’s Law

Equal volumes of gases at the same temperature and pressure contain the same number of molecules; one mole represents the amount of substance.

Molar volume

Volume occupied by one mole of a gas; under the same conditions, all gases have the same molar volume.

STPD

Standard Temperature and Pressure Dry: 0°C and 760 mmHg (dry gas).

22.4 L

Ideal molar volume of a gas at STPD: one mole occupies 22.4 liters.

Density

Mass per unit volume; high density indicates heavy particles, low density indicates light particles.

Gaseous diffusion

Movement of gas molecules from high to low concentration, spreading out until uniform.

Graham’s Law

Rate of diffusion of a gas is inversely proportional to the square root of its gram molecular weight.

Gram molecular weight (GMW)

Molar mass of a gas expressed in grams per mole.

Partial pressure

Pressure contributed by a single component of a gas mixture.

Dalton’s Law

Total pressure of a gas mixture equals the sum of its component partial pressures; each partial pressure is proportional to its fractional concentration.

Ptotal

Total pressure of a gas mixture.

Fractional concentration

The decimal fraction representing a gas’s percentage in a mixture.

Hyperbaric pressure

Pressure greater than atmospheric pressure.

Barometer

Device used to measure atmospheric pressure.

Mercury barometer

Barometer that uses a column of mercury to measure pressure.

Torr

Unit of pressure; 1 Torr equals 1 mmHg at sea level.

mmHg

Millimeters of mercury; unit of pressure used in barometry.

Aneroid barometer

Mechanical pressure gauge without liquid (uses springs) to measure pressure.

Manometer

Device to measure pressure using a liquid column; used at bedside for blood or airway pressures.

Pressure transducer

Device that converts pressure into an electrical signal (e.g., strain-gauge transducer).

Henry’s Law

The amount of gas dissolved in a liquid is proportional to its partial pressure above the liquid.

Solubility

The ability of a gas to dissolve in a liquid.

Solubility coefficient

The volume of gas that will dissolve in 1 mL of liquid at standard conditions; temperature affects solubility.

Dissolved gas volume

Volume of gas that dissolves in a liquid as predicted by Henry’s law.