《物理化学 Physical Chemistry》课程教学资源（英文版）The First Law（The Machinery）

The first law The machinery C Stephen L. Davis, 2003

The First Law The Machinery © Stephen L. Davis, 2003

Exact differentials ifz= f(, y)is an exact differential Bf dx af dy Ox) dz dX

Exact Differentials dx dy dz if z = f(x, y) is an exact differential, dz = f x dx f y dy y x           +      

Internal Energy Changes U=/ oU + T du=Id+ cr dt where I=0 for an ideal gas

Internal Energy Changes dU U V dV U T dT dU dV C dT T V T V T =       +       = + =      where  0 for an ideal gas

Thermodynamic ea'n of state P

Thermodynamic Eq’n of State p T p T V T −         =   

Expansion Coefficient tIny △全F△T, assuming constant a orlm(/7)=∫ad7

Expansion Coefficient                =         =  1 0 0 V V T V T V V T V V dT p p T T ln , ln( / )   assuming constant or

Isothermal Compressibility tIny y ap gp/n AV=-KTVAP, assuming K constant or In(V/V)=- Kdp

Isothermal Compressibility         T T T T T T p p V V p V p V V p V V dp  −       = −         − = −  1 0 0 ln , ln( / )   assuming constant or

Table of a and K T Substance a/10K- kT /10 atm Benzene 12.4 92.1 Diamond 0.030 0.187 ea 0.861 2.21 Water 2.1 49.6

Table of  and T Substance   −  − T / 10-6 atm Benzene 12.4 92.1 Diamond 0.030 0.187 Lead 0.861 2.21 Water 2.1 49.6

C and Cv ideal gas: CD-G=nR

Cp and CV C C TV C C nR P V T P V − = − =   2 ideal gas: