Thermodynamics Flashcards
Boundaries
Adiabatic and Diathermic
Types of System
Open : exchange of mass and energy
Closed : no exchange of energy
Isolated : no exchange of both mass and energy
Types of Properties
Extensive : Quantity Dependent (any sort of energy)
Intensive : Nature dependent
Types of functions
Path function : work and heat
State Function : everything except work and heat
Euler Theoram (for state functions only)
differentiation w.r.t. ‘y’ to ‘x’ = differentiation w.r.t. ‘x’ to ‘y’
Reversible Process
External Pressure = Pressure of Gas
Irreversible Process
External Pressure = Constant
Sign Conventions
For Work :
when work is done on the system (+ve)
when work is done by the system (-ve)
For Heat :
when heat is provided to the system (+ve)
when heat is lost by the system (-ve)
G.O.A.T. formula for Work
- External Pressure * Δ Volume
Work for Isothermal Reversible
- 2.303 * nRT * log(V2/V1)
- 2.303 * nRT * log(P1/P2)
Work for Isothermal Irreversible
G.O.A.T. formula for work
Work in ergs
1 Joule = 10^7 ergs
Work when gas expands
magnitude of Rev. Work > Magnitude of Irreversible Work
Work when gas compresses
magnitude of Rev. Work < Magnitude of Irreversible Work
Conventions for Δ V (when gas expands or compresses)
When gas expands :
ΔV = +ve
W = -ve
when gas compresses :
ΔV = -ve
W = +ve
Change in Internal Energy (ΔU)
q + W
Δ Kinetic Energy + Δ Potential Energy
ΔU for different Processes
Isothermal :
ΔU = 0 (q = -W)
Isochoric :
ΔU = q(volume constant)
Isobaric :
ΔU = q + W
Adiabatic :
ΔU = W
Enthalpy (H)
U + PV
Change in enthalpy (ΔH)
ΔU + ΔPV
Formulae for thermochemistry :
ΔU + PΔV
ΔU + Δn(gas)RT
1 atm pressure in Joules
1 atm = 101.3 Joules
Sign convention of work for cyclic processes
If clockwise arrows : -ve
If anticlockwise arrows : +ve
Heat Capacity (C)
Energy required to increase temperature by 1°
Types of Heat Capacity
SPECIFIC HEAT (S) : energy required to increase temperature of 1 gram system by 1°
q = mSΔT
MOLAR HEAT CAPACITY (Cm) : energy required to increase temperature of 1 mole by 1°
q = nC(molar)ΔT
Molar Heat Capacity types
At constant pressure = ΔH/ΔT
At constant volume = ΔU/ΔT
C(p)»_space; C(v)
C(p) - C(v) =
nR
Molar Heat capacity Ratio
C(p) / C(v)
