Solution cont. System boundary Entropy balance: (isolated system>no entropy transfer) s=) Metal bar: Water: Tmi =1200K Twi=300K cm=0.42kJkg·K Cw =4.2 kJ/kg.K mm =0.3 kg mw=9 kg △Swater+△Smetal "disorder" For incompressible substances: mc nsi Tr +mmCm In Entropy change of metal =(9kg) kJ +ao(ae) )303 k 303 Entropy change of waterT- 42 g·K 1200 -01734 0.2027kJ/K 上游充通大 April 23,2019 8 SHANGHAI JLAO TONG UNIVERSITYApril 23, 2019 8 Solution cont. Entropy balance: (isolated system  no entropy transfer) For incompressible substances: Entropy change of water↑ Entropy change of metal ↓ “disorder