BioPHYSICAL chemistry

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3.13 Consider a piece of paper burning in a closed, adiabatic, constant-volume container that
has an oxygen atmosphere. Are the following changes positive, zero, or negative? (a) The
change in internal energy; (b) the change in entropy of the system; (c) the change in entropy
of the surroundings.
3.14 Calculate the standard enthalpy of formation for the oxidation of sucrose, using standard
enthalpies of formation of −393.5, −285.8, and −2222 kJ mol−^1 for carbon dioxide, water, and
sucrose, respectively.
3.15 If a protein unfolds at 80°C with a standard enthalpy of transition of 500 kJ mol−^1 , what
is the associated entropic change?
3.16 Give some technical reasons for the improved gas mileage of a hybrid car.
3.17 How is a thermodynamic analysis of entropy and enthalpy changes used to indicate a favor-
able drug candidate?
3.18 Why is nitrogen fixation a slow process?
3.19 How do metal surfaces contribute to the Haber–Bosch process?
3.20 What is the role of nitrogenase in the nitrogen cycle?


70 PARTI THERMODYNAMICS AND KINETICS

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