Thermodynamics Flashcards
Extensive properties
Internal energy, heat cap, enthalpy, entropy, free energy
Intensive properties
P, MP, BP, density, viscosity, RI, conc, specific heat capacity
w by sys
-ve
Free expansion
Pext = 0 or in vacuum
For reversible process, Δu, ΔT =
0
Enthalpy ΔH =
ΔU + PΔV
q =
CΔT
Cp - Cv =
R universal gas const
ΔH or q(rev) =
TΔS
Solid to liq to gas, entropy
increases
2nd law
Entropy of universe increase for every spontaneous change
ΔStot > 0
spontaneous
Gibb’s free energy
ΔG = ΔH - TΔS
Tf =
9/5Tc + 32
L` =
L(1+αΔT)
A`=
AβΔT
α:β:γ
1:2:3
For pendullum ΔT =
1/2TαΔθ
Thermal stress
YαΔT
Specific Heat Capacity
Q = mSΔT
Specific heat cap of water =
4200 J/kg K
Heat capacity
Heat required by any obj by 1*
Final temp T =
m1S1T1 + m2S2T2/m1S1 + m2S2
Latent heat of fusion Lf =
Q/m
Conduction H =
KAΔT/L
Thermal resistance R =
ΔT/H = L/KA
Prevosts theory
All objs radiate
Absorptive power
a = Energy absorbed/Energy incident
Emissive power
E = Q/At
emissivity =
Ebody/Eblackbody
Kirchoff’s laws
Absorbers are good emitters
e = a
Stefan-Boltzmann law
E = eσT^4
Wien’s displacement law
λ = b/T
b = 2.88/10^3
Newton’s law of cooling
Rate of cooling prop (Tbody-Tsurr)
θ1-θ2/T = k[(θ1+θ2)/2 - θsurr]
For adiabatic process, PV^γ =
const
γ =
Cp/Cv
Efficiency η =
W/Q1
Kelvin Planck
No process is possible whose sole result is absorption of heat & complete conversion of heat to work
P =
1/3Nm(Vrms)^2/Vol
Vrms =
√3P/ρ
Most probable speed Vmp
√2RT/M
Vavg =
√8RT/πM
Translational KE
3/2nRT = 3/2PV
Degrees of freedom for monoatomic
3
Degrees of freedom(f) for diatomic
5
Law of equipartition
Energy that ever molecule gets in 1 degree is 1/2k(B)T
n mole =
n f/2 RT
Cv =
f/2 R
Cp =
(f+2)R/2
γ for law of equipartition
γ = (f+2)f
mean free path
λ = 1/√2nπd^2
relaxation time =
λ/V
Collision freq =
√2nπd^2V
