Gas Laws

Kinetic Molecular Theory: 6.022 x 10^23 particles of gas in an area of a home printer.

Assumptions of KMT of gases

1. Gases move in a random straight line until they collide with something (wall or another particle).

2. All collisions are perfectly elastic (no energy lost due to collisions).

3. Gases do not attract each other. (No forces of attraction.)

4. Gas particles have no volume.

5. Temperature measure average kinetic energy.

Formula for Kinetic Energy

KE = (1/2)mv²
m = mass
v = velocity

Mass vs. Temperature Rule

Less mass at the same temperature will have a greater speed.

Effusion

Gas escaping through a hole.

Diffusion

Gas particles expanding to fill the space

Ideal Gas Formula

PV=nRT

Units of Pressure Equivalence

1 atm = 101.3 kPa = 760 mmHG = 760 Torr

R-value in Ideal Gas Formula

• Constant

• Corrects VnT based on unit of P

Unit for Temperature

• Kelvin

  • 0 C = 273 K

R for atm

0.08206

R for kPa

8.314

R for Torr

62.36

R for mmHg

62.36

Gas Laws

1. Avogadro’s Law

2. Boyle’s Law

3. Charles’ Law

4. Gay-Lussac Law

Avogadro’s Law

V1/n1 = V2/n2

Boyle’s Law

P1V1 = P2V2

Charles’ Law

V1/T1 = V2/T2

Gay-Lussac Law

P1/T1 = P2/T2

Combined Gas Law Formula

P1V1/n1T1 = P2V2/n2T2

Density Gas Formula Variation

PM = pRT

Molar Mass/Mass Gas Formula Variation

PMV = mRT

Dalton’s Law of Partial Pressure

Ptot = P1+P2+P3+…

Dalton’s Law of Partial Pressure for Water Displacement

Ptot = Pgas+PH20