Internal Energy Sensible and latent energy --sum of all microscopic forms of energy Chemical energy U Transl. Nuclear energy Rotat. Uth U=U(T,v) U。-方亿，y以。 or f T.p or U=U(T,p) U as a Function of T at Constant P U as a Function of P at Constant T U as a Function of P at Constant T Real gas Internal energy is Increasing T increases molecular a strong function Internal energy is of temperature a weak function vibrations,rotation and of pressure at Intemal energy is not a function of most Tand P U translation U increases as U pressure well. Ideal/Real Increasing P decreases U slightly gas Real gas Ideal gas at most values of T and P.due to P complex molecular interactions. If ideal gas,P do not affect U 上降文通大学 March 5,2019 11 SHANGHAI JLAO TONG UNIVERSITY
March 5, 2019 11 Internal Energy U Uch Unu Uth Uk Transl. Rotat. Vibr. f T 1 Up — f T,v 2 U U(T,v) -- sum of all microscopic forms of energy 2 or , f T p or ( , ) U U T p Increasing T increases molecular vibrations, rotation and translation U increases as well. Increasing P decreases U slightly at most values of T and P. due to complex molecular interactions. Real gas Real gas Ideal/Real gas Ideal gas If ideal gas, P do not affect U
Macroscopic/Microscopic Energy Difference Microscopic kinetic energy of molecules (does not turn the wheel) Dam ater Macroscopic kinetic energy (turns the wheel) 上游充通大 March 5,2019 12 SHANGHAI JIAO TONG UNIVERSITY
March 5, 2019 12 Macroscopic/Microscopic Energy Difference