What is pressure?
Pressure = Force/ area = N/ m^2 = pascal

What is atmospheric pressure?
The weight of the air pushing down on you.

• standard atmospheric pressure =
• 1 atm = 101.3 kPa= 760 mmHg = 760 Torr= 1.013 bar= 14.7 psi

How is atmosphere pressure measured?
Barometer

Boyle's Law : P & V

V up, P down
P1 * V1 = P2 * V2
real life example : car engines

Charles's Law : V & T

V up, T up
V1 / T1 = V2 / T2
real life example : baking, hot air balloon

Gay Lussac's Law : P & T

P up, T up
P1 / T1 = P2 / T2

Combined Gas Law :

(P1 * V1) / T1 = (P2 * V2) / T2

Ideal Gas Law :

PV = nRT

n = m / M
moles of gas = mass of gas / molar mass of gas

Density :

m / V = PM / RT

Dalton's Law of Partial Pressures:
Ptotal=P1+P2+P3...Pn= ntotal(RT/V)



Avogadro's Hypothesis :

equal volumes of gas under the same pressure and temperature have equal number of moles

Kinetic Molecular Theory

• The average kinetic energy of the gas molecules is proportional to the gas temperature.
• If two gases have the same temp, they have the same average KE
• KE= (1/2)mv^2

The space between gas molecules is so big compared to the size of the actual molecules themselves
Molecules are in continous random motion
When gas molecules collide, it is a perfect elastic collision w/ no loss of enrgy

*Although temp tells you average, there are some molecules going fast and slower. At higher temp -> move faster *Since KE is mass and velocity, heavier gases have slower speed.

Maxwell's Expression

• Diffusion is the mixing of two or more gases due to their molecular motion. (molecules of two gases will completely mix)
• Effusion is the movement of gas through a tiny opening in a container into another container where pressure is low

Rate of effusion is inverse to the square root of molar mass: