Gases

gaseous state

totally disordered state of matter in which the molecules move constantly in rapid, random translational motion. The macroscopic properties of gases reflect this microscopic behavior.

PV=nRT

P= pressure in atm

V= volume in liters

n=amount in mols

T=temp in kelvin

R=ideal gas law constant

R =

0.08206 L x atm/mols x k

STP

standard temperature and pressure

5 standard pressures

• 1.00 atm

• 760 torr

• 760 mm of Hg

• 14.7 psi

• 101.3 kPa

Ideal gases

act according to kinetic molecular theory gases act more ideally at high temp and low pressures

Real gases

when gases don’t act ideally

When do gases act real

• low temp

• high pressure

Ideal Gas Law

PV=nRT

charles law

at a constant pressure the volume of a gas is directly proportional to the absolute temp

boyles law

at a constant temp the pressure of a gas is inversely related to volume

avogadros law

at a constant temperature and pressure the volume of a gas is directly proportional to the number of gas particles

Gay Lussacs law

at a constant volume the pressure of a gas varies directly with absolute temp

Daltons Law

the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture

Graham’s Law

the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles

Characteristics of Gases

• easily compressed

• expand to fill available volume

• exert a uniform pressure

• miscible

• rapid diffusion

1 mol of any gas at STP has what volume

22.4 L

Diffusion

movement of one gas through another

Effusion

passage of a gas through the tiny orifice into an evacuated chamber