Problems
3.1 If heat is transferred reversibly from the environment into a system with no other changes,
what can be said about the entropy change of the system?
3.2 Calculate the change in entropy when 25 kJ of energy is transferred reversibly and isotherm-
ally as heat to a large block of iron at (a) 20°C and (b) 200°C.
3.3 For a spontaneous process at constant pressure, how will the Gibbs energy change?
3.4 If a process results in the entropy change for the surroundings being negative, and the
pressure is held constant, what can be said about the heat change?
3.5 Calculate the change in molar entropy when a monatomic perfect gas is compressed to half
its volume.
3.6 Calculate the change in molar entropy when a monatomic perfect gas is initially compressed
to half its volume and then expanded back to the original volume.
3.7 Calculate the Carnot efficiency of a primitive steam engine operating on steam at 100°C
and discharging at 20°C. How does the efficiency change if the discharge temperature is
60°C?
3.8 Determine the value of the entropy and enthalpy change for the process if the temperature
dependence for the Gibbs energy at constant pressure is given by ΔG=−85 J +(30 J K−^1 )T.
3.9 When heat is transferred from a hot block to a cold block, what can be said about the
entropy change of each block?
3.10 If the equilibrium constant is greater than one, what can be said about the change in the
Gibbs energy?
3.11 For a spontaneous reaction, what can be stated about the entropy change?
3.12 What can be said about the total entropy change for the reversible expansion of an ideal
gas?
CHAPTER 3 SECOND LAW OF THERMODYNAMICS 69
References
Ahn, N.G. and Resing, K.A. (2005) Lessons in rational
drug design for protein kinases. Science 308 , 1266 –7.
Barney, B.M., Lee, H.I., Dos Santos, P.C. et al.
(2006) Breaking the N 2 triple bond: insight into the
nitrogenase mechanism. Dalton Transactions 2006 ,
2277– 84.
Cohen, M.S., Zhang, C., Shokat, M., and Tauton, J.
(2005) Structural bioinformatics-based design
of selective, irreversible kinase inhibitors. Science
308 , 1318 –21.
Demirdoven, N. and Deutsch, J. (2004) Hybrid cars,
fuel cell cars and later. Science 305 , 974 – 6.
Ferguson, S.J. (1998) Nitrogen cycle enzymology.
Current Opinion in Chemical Biology 2 , 182–93.
Freire, E. (2002) Designing drugs against heterogen-
eous targets.Nature Biotechnology 20 , 15 –16.
Freire, E. (2004) Isothermal titration calorimetry:
controlling binding forces in lead optimization.
Drug Disco 9 ery Today: Technologies 1 , 295 –9.
Howard, J.B. and Rees, D.C. (1996) Structural basis
of biological nitrogen fixation. Chemical Re 9 iews 96 ,
2965 – 82.
Noble, M.E.M., Endicott, J.A., and Johnson, L.N.
(2004) Protein kinase inhibitors: insights into drug
design from structure. Science 303 , 1800 –5.
Rees, D.C. and Howard, J.B. (1999). Structural bio-
energetics and energy transduction mechanisms.
Journal of Molecular Biology 293 , 343 –50.
Teague, S.J. (2003) Implications of protein flexib-
ility for drug discovery. Nature Re 9 iews 3 , 527–
41.