THERMO6 Flashcards
State Variables
- P, V, T, Eint are state variables
- this means that once a point is marked on a P-V diagram (for a fixed sample) defines all of these variables
Are Q and W state variables?
No, they are a measure of energy that flows into/out of a system and depend on the route taken between points on a PV diagram rather than the positions of the points themselves
Equations that always true for both real gases
ΔEint = Qin + Won Won = -∫P dv
Equations that are always true for ideal gases
ΔEint = Qin + Won Won = -∫P dv PV = nRT ΔEint = CvΔT Eint = DoF*n*1/2 RT
Isobaric Process
Definition
ΔP = 0
e.g. experiment is open to the atmosphere
Isochoric Process
Definition
ΔV = 0
e.g. experiment takes place in a rigid container
Isothermal Process
Definition
ΔT = 0
a slow process to allow heat to flow in or out of the system to maintain temperature
all energy entering the system is used to do work rather than to increase the internal energy
Adiabatic Process
Definition
Qin = 0
e. g. insulated processes
- usually have to be very rapid to prevent any flow of energy into or out of the system
Isobaric Process
Won
Won = -PΔV
Isobaric Process
Qin
Qin = ΔEint - Won = CvΔT + PΔV
Isobaric Process
ΔEint
ΔEint = CvΔT
Isochoric Process
Won
Won = 0
Isochoric Process
Qin
Qin = ΔEint
Isochoric Process
ΔEint
ΔEint = CvΔT
Isothermal Process
Won
Won = nRT ln(Vi/Vf)
