Assignment 2(thermodynamics) (CML100) Q1: One mole of a gas is expanded isothermally at 298 K until its volume is tripled. Find the value of Sgas and Stotal under the following conditions? (a)Expansion is carried out reversibly. (b) Expansion is carried out irreversibly where 836.8 J of heat is less absorbed than in case (a). © Expansion is free. Q2. 5 gm of ice at 273 K is added to the 30 gm of water at 323 K in a thermally insulated container (a) what is the final temperature? (b) What is the total entropy change? Hfus of ice at 273 K = 334.72 J/gm Hvap of water at 373 K= 2259.26 J/gm Average heat capacity of the liquid water = 4.184 JK-1gm-1 Q3. A certain gas obeys the equation of state PVm = RT (1 + bP+cP2) where b and c are constants. Find expressions for Hm and Sm for a change of state of this gas from (P1, T1) to (P2, T2). Neglect the temperature and pressure dependence of Cp,m. Q4. Derive the following relation 2G C p T 2 T P Q5. The purest acetic acid is often called glacial acetic acid because it is purified by fractional freezing at its melting point at 16.6 °C. A flask containing several moles of acetic acid at 16.6 °C is lowered into an ice-water bath briefly. When it is removed it is found that exactly 1 mole of acetic acid is frozen. (a) What is the change in the entropy of acetic acid? (b) What is the change in entropy of the water bath? (c) Now consider that the water bath and acetic acid are in the same system. What is the entropy change for the combined system? Given f H (CH 3COOH ) = 11.45 kJ mol-1 and f H ( H 2O ) = 5.98 kJ mol-1
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