The Gas Phase

conversions

1 atm = 760 mmHg = 760 torr = 101,325 Pa

STP

0 degrees C or 273 K, 1 atm

standard conditions

25 degrees C or 298 K, 1 atm, 1M

Boyle’s Law

PV = k or P1V1 = P2V2

Charles’s Law

V/T = k or V1/T1 = V2/T2

Gay-Lussac’s Law

P/T = k or P1/T1 = P2/T2

Avogadro’s Principle

n/V = k or n1/V1 = n2/V2

combined gas law

P1V1/T1 = P2V2/T2

ideal gas law

PV = nRT

real gases

decreasing volume makes it behave less ideally

deviations in pressure

at high pressure, volume is less than predicted due to intermolecular attractions

deviations in temperature

as temperature decreases, average velocity decreases and attractive intermolecular forces become more significant, at low temps larger volume is predicted

1 mole of gas at STP

22.4 L

Dalton’s Law

Pt = PA + PB + PC, PA = PTXA

XA

nA/nT, nA = moles of A, nT = total moles

kinetic molecular theory of gases

explains gaseous molecular behavior based on motion of individual molecules

average molecular speed

temperature of system dictates speed of a gas molecule

average molecular speed equation

K = 0.5mv² or 3/2 kB T