Thermodynamics Flashcards
Boyle’s Law
p ∝ 1/V
Lussac’s Law
V ∝ T (in K)
Charles’ Law
p ∝ T
The ideal gas Law
pV = nRT
1 bar in Pascals or N m^(-2)
1 x 10^5 N m^(-2)
Converting from °C into K
+ 273.15
For 2 gases A and B, what are their partial pressures?
PA = (nA RT) / V PB = (nB RT) / V
Total pressure = PA + PB
Assumptions for the ideal gas Law
The molecules take up no volume
No interactions between molecules
Van der Waals equation of state and what a and b account for
(nRT / V - nb) - (an^2 / V^2)
a corrects for attractive interactions, which would reduce the pressure from an ideal gas
b corrects for volume of molecules, which would increase the pressure from an ideal gas
ΔU =
Internal energy change
Internal energy =
U(translation) + U(rotation) + U(vibration) + U(electronic)
For an ideal gas we only need to consider U(translation)
The Equipartition principle
for each degree of freedom, we get 0.5kT of energy (0.5 RT per mol)
U = 3/2 R
1st Law of thermodynamics
ΔU = q + w
What does isochoric mean?
Constant volume
–> dV = 0
What does isobaric mean?
Constant pressure (1st law unchanged)