Applied thermodynamics(lecture 4)gas laws

*Gas Laws*

Physical Characteristics of GasesPhysical Characteristics Typical Units

Volume, V liters (L)

Pressure, P atmosphere

(1 atm = 1.015x105 N/m2)

Temperature, T Kelvin (K)

Number of atoms ormolecules, n

mole (1 mol = 6.022x1023

atoms or molecules)

Pressure and volumeare inversely related atconstant temperature.

PV = K

As one goes up, the othergoes down.

P1V1 = P2V2

Boyle’s Law

“Father of Modern Chemistry”Robert Boyle

Chemist & Natural PhilosopherListmore, Ireland

January 25, 1627 – December 30, 1690

Boyle’s Law: P1V1 = P2V2

Boyle’s Law: P1V1 = P2V2

Volume of a gas variesdirectly with the absolutetemperature at constantpressure.

V = KT

V1 / T1 = V2 / T2

Charles’ Law

Jacques-Alexandre CharlesMathematician, Physicist, Inventor

Beaugency, FranceNovember 12, 1746 – April 7, 1823

Charles’ Law: V1/T1 = V2/T2

Charles’ Law: V1/T1 = V2/T2

At constant temperatureand pressure, the volume ofa gas is directly related tothe number of moles.

V = K n

V1 / n1 = V2 / n2

Avogadro’s Law

Amedeo AvogadroPhysicist

Turin, ItalyAugust 9, 1776 – July 9, 1856

Avogadro’s Law: V1/n1=V2/n2

At constant volume,pressure and absolutetemperature aredirectly related.

P = k T

P1 / T1 = P2 / T2

Gay-Lussac Law

Joseph-Louis Gay-LussacExperimentalistLimoges, France

December 6, 1778 – May 9, 1850

The total pressure in a containeris the sum of the pressure eachgas would exert if it were alone

in the container.

The total pressure is the sum ofthe partial pressures.

PTotal = P1 + P2 + P3 + P4 + P5 ...

(For each gas P = nRT/V)

Dalton’s Law

John DaltonChemist & Physicist

Eaglesfield, Cumberland, EnglandSeptember 6, 1766 – July 27, 1844

The Characteristic equation of a perfect gas

The Specific heat Capacities of a gas

The Constant volume heating of a gas

The Constant pressure heating of a gas

The Difference of the Specific heat Capacities of a gas

The Polytropic process and a gas