Thermal Flashcards
zeroth law of thermodynamics
If C is initially in thermal equilibrium with both A and B then A and B are also in thermal equilibrium with eachother
First law of thermodynamics
delta U = Q + W
Internal energy of an ideal gas
depends only on its temperature not on its pressure or volume
Heat capacity of an ideal gas
Cp=Cv+R
Cp
molar heat capacity at constant pressure
Cv
molar heat capacity at constant volume
relationship between Cp and Cv
gamma = Cp/Cv
Adiabatic process for an ideal gas
PV^gamma = constant TV^(gamma-1) = constant
kinetic theory of gases
PV=1/3Nm
PV=2/3N
u
total internal energy
PV for monatomic gas
PV = 2/3 U
PV gamma relation
PV=(gamma-1)U
Clausius 2
It is impossible to construct a cyclical machine whose sole effect is to transfer energy continuously by heat from one object at a higher temperature without the input of energy by work.
Kelvin-Planck
it is impossible to construct a heat engine that, operating in a cycle produces no effect other than the input of energy by heat from a reservoir and the performance and an equal amount of wor
efficiency equation
e=W/Qh
efficiency equation
e=W/Qh = (Qh-Qc)/Qc = 1-Qc/Qh
adiabatic QU
Q=0
delta U = W
Isothermal QUW
delta U =0 Q=-!
four stages of an ideal carnot engine
isothermal expansion
adiabatic expansion
isothermal compression
adiabatic compression
entropy equation
Q1/T1 = S = Q2/S2
Change in entropy in isothermal expansion
increase in entropy S = Qh/Th
change in entropy in isothermal compression
decrease in entropy S=Qc/Tc
Reversible process
- the intermediate steps are known
- the system is never far from equilibrium
- the system can be returned to its original state
irreversible process
- the intermediate steps are not known
- non-equilibrium states are involved
- it is not possible to run backwards, occurs naturally in one direction only.
What is the enclosed part of a Carnot cycle graph
The work done
