Chapter 5 - Gases Flashcards
Diffusion
Process where gas molecules spread out in response to a concentration gradient.
Effusion
- Process where gas escapes from a container into a vacuum through a small hole.
- Rate of Diffusion is inversely proportional to the square root of the molar mass.
Torr
1 torr = 1 mmHg
Atmosphere
1 atm = 760 mmHg
Pascal
1 Pa = 1 N/m2
Boyle’s Law
Volume is inversely related to pressure.
V ∝ 1/P
P1V1 = P2V2
Charles’ Law
Volume is directly proportional to temperature.
V ∝ T
V1 / T1 = V2 / T2
Avogadro’s Law
Volume is directly proportional to moles of gas.
V ∝ n
V1 / n1 = V2 / n2
Ideal Gas Law
PV = nRT
Molar Volume
The volume occupied by one mole of a substance.
Density (gas)
- d* = ρM / RT
- ρ* = molar density
- M* = Molar Mass
Dalton’s Law of Partial Pressures
Ptotal = Pa + Pb + Pc +…..
Mole Fraction (Xa)
Xa = na / ntotal
Partial Pressure of a Gas
Pa = XaPtotal
Kinetic Molecular Theory
A model of an ideal gas as a collection of point particles in constant motion undergoing completely elastic collisions.
Kinetic Molecular Theory Assumptions
- The size of a particle is negligibly small.
- The average kinetic energy of a particle is proportional to the temperature (K).
- The collision of one particle with another (or with the walls of its container) is completely elastic.
Kinetic Energy of a particle
KE = ½mv2
Mean Square Velocity
Urms = √(3RT / M)
Mean Free Path
The average distance that a molecule travels between collisions.
Diffusion
The process by which gas molecules spread out in response to a concentration gradient.
Effusion
The process by which a gas escapes from a container into a vacuum through a small hole.
Graham’s Law of Effusion
ratea / rateb = √(MB / MA)
