# Thermodynamics of Chemical and Biological Systems

Note : Attempt all questions.

(a) Write down the mathematical form of the First Law of Thermodynamics and justify this formulation. Identify the state and path functions in this expression.

(b) How is enthalpy defined? Mention the measurable quantity in terms of which the enthalpy change in a process can be determined.

(c) What do you mean by polytropic process? Discuss its application for a non-ideal gaseous system.

(d) Deduce the general expression for the variation in Cv with volume change and Cp with pressure change, keeping temperature constant. Predict, based on these expressions, the values

(e) How the work done and ethalpy changes are calculated in isobaric (constant pressure) and isochoric (constant volume) process involving ideal gases?

(f)  What is meant by a reversible process? Discuss the merits and demerits of such processes.

2.  Attempt any four :

(a) What is Charle’s law and how it is applicable for gases? Illustrate how it leads to the definition of absolute temperature scale. Write down one equation of state applicable for real gases.

(b) What is meant by partial pressure of a constituent gas in a gaseous mixture? State and explain the Dalton’s law of additive pressure.

(c) State the Dulong and Petit’s law regarding the specific heat of solids and give its justification.

Also comment about its validity and limitations.

(d) What is Trouton’s rule applicable for phase transition from liquid-to-vapour? Comment about the generality of this rule.

(e) How do you define the heat of combustion? Describe briefly the method for its determination.

(f)  What is flame temperature? Illustrate how the maximum attainable temperature of a flame can estimated.

3.  Attempt any two :

(a) (i) State and illustrate the second law of Thermodynamics. Provide the mathematical statement of the second law.

(ii) Show that the entropy is a state function.

(b) Discuss the application of second law of thermodynamics to steady and unsteady flow systems.

(c) Describe briefly the ATP ADP cycle

which plays a pivotal role in the production of biological energy.

4.  Attempt any two :

(a) Illustrate, with suitable example, the procedure for calculating the standard free energy change in a biological reaction.

(b) What is the basic thermodynamic criterion for a reaction to occur spontaneously? The reaction of glucose with HP042- ions to yield glucose-6-phosphate is energetically unfavourable but its occurrence becomes possible with the involvement of ATP. Explain the reason for the same based on thermodynamics parameters.

(c) Discuss the salient aspects of the enzymatic transfer of phosphate groups to ADP.