·Isolated system: There is no exchange of matter and energy between the system and the environment

·Closed system: There is energy exchange between the system and the environment, but no material exchange.

·Open system: There is exchange of matter and energy between the system and the environment

·①The changes in the state function X caused by small changes in the system state can be expressed by the total differential dX

·②The change of the system from state a to state b △X=Xb-Xa is only related to the beginning and ending states, and has nothing to do with the change path or experience

·When the environment does work on the system, W>0

·When the system does work on the environment, W

·The definition of work is δW=-Fdl=-pamb-dV

·Constant external pressure process W=-pamb·△V

·The system absorbs heat from the environment, Q>0

·The system releases heat to the environment, Q

·Thermodynamic energy

·Energy cannot be created or destroyed out of thin air, it can only be transformed from one form to another.

·△U=Q W

·For infinitesimal processes, dU=δQ δW

·For ideal gases, thermodynamic energy U is only a function of temperature T, (aU/aV)F=0

·Under constant volume state, Qv=△U, δQ=dU

·Under constant voltage, W volume =-pamb-(V2-V1)=p1V1-p2V2

·When the non-volume work is 0, Qp=(U2 p2V2)-(U1 p1V1)

·Let H=U pV·Qp=△H, δQp=dH (applicable to processes with constant pressure or isobaric pressure and non-volume work is 0)

·Cv,m=1/n(δQv/dT)(unit: J·mol-1·K-¹)

·When a system with an amount of substance n undergoes a simple pVT change of constant volume: Qv=△U=nʃT2 T1Cv,mdT(△U=Qv)

·If there is no constant capacity, △U=n∫T2 T1Cv,mdT(ΔU≠Qv)

·Cp,m=1/n(δQp/dT)

·A system with an amount of material n undergoes a simple pVT change process at constant pressure, Qp=△H=n∫T2 T1Cp,mdT

A system with an amount of material n undergoes a simple pVT change process with non-constant pressure.

·①Ideal gas H=U nRT,△H=n∫T2 T1Cp,mdT

·②Condensed matter (referring to substances in liquid or solid state), △U=△H=n∫T2 T1Cp,mdT

·Monoatomic ideal gas: Cv,m=3/2R,Cp,m=5/2R

·Diatomic ideal gas: Cv,m=5/2R,Cp,m=7/2R

·Polyatomic ideal gas: Cv,m=3R,Cp,m=4R

·For condensed matter, Cv,m and Cp,m can be considered to be approximately equal

·Cp,m=Qp/(n(T2-T¹))=JCp,m dT/(T2-T1)

·Molar phase change enthalpy

·△rHm(T)=△Hm(T0) ʃT2 T1[Cp,m(β)-Cp,m(α)]dT

·Reaction progress: ξ=ΔnB/vB (for the same chemical reaction, the chemical reaction progress represented by each component is the same)

·Molar reaction enthalpy

·Gas: Any temperature T, pressure pθ=100kPa and exhibits the pure gas state of an ideal gas

·Liquid or solid: Pure liquid or pure solid state at any temperature and pressure pθ=100kPa standard pressure

·The relationship between Qp,m and Qv,m

·Standard molar enthalpy of formation (ΔfHmθ):ΔrHmθ=Σ[vBΔfHmθ(B)]

·Standard molar enthalpy of combustion (ΔcHmθ): ΔrHmθ=Σ[vBΔcHmθ(B)]

·Change of △rHmθ with temperature T—Kirchhoff’s formula

ΔrHmθ(T)= ΔrHmθ(298.15K) ΔrCp,m(T-298.15K)

·Reversible process

·Calculation of reversible volume work

①Ideal gas constant temperature reversible volume work WT,r:WT,r=nRTln(V1/V2)=nRTln(p2/p1)

②Adiabatic reversible volume work of ideal gas Wa,r

i. Ideal gas adiabatic reversible equation

T1/T2=(V1/V2)γ-1 or TVγ-1=constant

T1/T2=(p1/p2)(γ-1)/γ or Tp(γ-1)/γ=constant γ=Cp,m/Cv,m is called the ideal gas heat capacity ratio. These three formulas are applicable to the body adiabatic reversible process

p1/p2=(V1/V2)γ or pVγ=constant

ii. Ideal gas adiabatic reversible volume work Wa,r

Wa,r=ΔU=nRTCv,m(T2-T1)

·Joule-Thomson experiment

·Thermodynamic characteristics of throttling expansion

Joule-Thomson coefficient (throttle expansion coefficient): μJ-T=(аT/аp)H

μJ-T>0, gas throttling and expansion produces a refrigeration effect

μJ-T gas generates heating effect after throttling and expansion