Ice at -5 C is heated to become vapor with temperature of 110 C at atmospheric pressure. The entropy change associated with this process can be obtained from
- 268 K273 K Cp,m dT + Hm, fusionTf + Hm, vaporisationTb + 273 K373 K Cp,m dT + 373 K383 K Cp,m dT
- 268 K383 K Cp dT + Hmelting273 + Hboiling373
- 268 K383 K Cp dT + qrevT
- 268 K273 K Cp,mT dT + Hm, fusionTf + Hm, vaporisationTb + 273 K373 K Cp,m dTT + 373 K383 K Cp,m dTT
Answer
(4) 268 K273 K Cp,mT dT + Hm, fusionTf + Hm, vaporisationTb + 273 K373 K Cp,m dTT + 373 K383 K Cp,m dTT
Solution
Concept: S = Cp dTT on heating, S = HT at a phase change.
Path: ice 268→273 K, melting at Tf, water 273→373 K, vaporisation at Tb, steam 373→383 K.
∴ three heating terms + two phase-change terms ⇒ option (4)
Answer: (4)