Gas law Flashcards
Pressure
Units of pressure
1atm= 101.3kPa=760mmHg=760 Torr= 14.7
Force per unit area
Pressure
Rate of molecular collision
Temperature
Average molecular speed
Gas Laws Boyle
PV=k P1V1 = P2V2 P = pressure V=volume k=constant at a specific temp
Ideal gas behaviour
V is inversely proportional to P, if we graph it and straight line shows.
Charles’ Law
Volume and temperature are proportional with a fixed amount of gas
V1/T1= V2T2
Avogadro’s Law
Volume is proportional to the Number of moles of gas at Constant P and T
V1/n1=V2/n2
Ideal Gas Law
PV = nRT
Molar mass of a gas
n= mass/molar mass = m(g)/ MW P=nRT/V = mRT/molar mass V= dRT/ Molar Mass
Vapour Pressure
The pressure that results from a liquid when
rate of evaporation = Rate of condensation in a closed container
Temperature Dependent
Kinetic Molecular Theory of Gases
- Volume of each particle can be neglected
- Pressure results from the particle’s collision against the walls of the container
- Particles do not exert forces onto another
- Average kinetic energy of a gas particle is directly proportional to the temperature
Roots mean square velocity
Average of the squared velocity of the particles
u^2
Maxwell distribution law
Average distance a particle travels between collisions
Collision between particles = large range in velocity
Effusion
Measures rate at which the gas is transferred into the chamber
Rate of effusion of gas 1/ Rate of effusion gas 2 = square root molar mass 2 / square root molar mass 1
Collision with container walls
Collision rate
Depends on
Particle speed (Uavg)
Area (A)
Particle Density (# of particles / Volume = N/V)
Ideal gas
behave ideally at low P/ High T
- Negligible particle Volume
- NO inter particle forces (attraction/Repulsion)
- Plot of PV/nRT vs P is unity = 1
Ideal Behaviour in real gases
Low temp
-Few particles per unit volume
-Volume of particles is negligible compared to the volume of the container
- Interactions are minimized
Behaves more like ideal gas at low pressure
Ideal Behaviour in real gases
Gas at high temp
Less interaction, particles move further apart, larger volume
at low temp, volume decreases, particles closer together
Real gas behaves more like an ideal gas at high temp
