Thermodynamics - lecture 1 Flashcards
What is an isolated system?
System which exchanges neither energy nor matter
Which variables are relevant for an isolated system?
N
V
U
What is a closed system?
System which exchanges energy but not matter
Which variables are relevant to a closed system?
N
V
T
What is an open system?
System which exchanges energy and matter
What do the variables N, V , P, U and T mean?
N = Number of moles V = Volume P = Pressure U = Energy T = Temperature
What is the ideal gas equation?
pV = nRT
What is the Van der Waals gas law?
p = nRT / V-nb - a(n/v)²
What do a and b stand for in the Van der Waals gas law?
a = attractive interactions b = repulsive interactions
What are a and b in the Van der Waals gas law?
constants that depend on the particular gas
What is the Van der Waals gas law used for?
Non-ideal gases
What is work?
The transfer of energy by the application of a force
What is the equation for work?
W = - p (Vғ - Vᵢ ) = - pΔV
What is the work done ON the gas when compressed?
Positive
What is the work done BY the gas when compressed?
Negative
Equation relating work done and work by gas?
Work done on the gas = - work done by the gas
What is the change in volume for compression?
ΔV < 0
What is the change in volume for expansion?
ΔV > 0
What is heat?
Transfer of energy down a temperature gradient
What is the equation for heat?
q = C (Tғ - Tᵢ) = CΔT
What are the units for heat?
q = Joules (J)
What are the units for C?
J K⁻¹
What is the equation for heat with molar heat capacity?
q = n Cᴍ(Tғ - Tᵢ) = nCᴍΔT
What are the units for Cᴍ?
J K⁻¹ mol⁻¹
