Question

5.(a) Define the term Gibbs free energy (2 marks) (b) Give a mathematical expression of the entropy according to (0 statistical thermodynamics and () classical thermodynamics. (4 marks) (c) Based on a statistical thermodynamics argument explain why the entropy of a gas increases when heat is supplied to it. (3 marks) (d) Define the chemical potential uA of a gas Ag) of partial pressure PA present in a mixture of gases. (2 marks) The products of the oxygen (02) is sulfur trioxide (SO3). Table Q5 shows themodynami (e) oxidation of sulfur dioxide (SO2) with molecular data, at 298 K, for the reagents and products of the reaction. Table Q5 SO3 SO2 O2 256.8 248.2 205.1 -395.7 902432.8 (i) Write a balanced chemical equation for the reaction. (ü) Calculate the standard enthalpy of reaction A,HP. (ii) Calculate the standard entropy of reaction 4,S (iv) Giving reasons for your answer, explain if the reaction is (2 marks) (4 marks) (4 marks) spontaneous under standard conditions. (4 marks)

Answer 1

Gibb's free energy G = U_TS + PV = F + PV = F + PV = H - TS Gibb's energy in the thermodynamic potential that minimizes during an and isobaric process i e For isothermal isobaric process dG lessthanorequalto 0 (equality hold only for changes) b) statistical Thermodynamic: S = K_3 ln z E/g + S_0 factorial Control OR S = k_0 ln z + E/T Classical Thermodynamic Z is partition function E is average Energy of the system as Temperature T S = integral^_S theta/T + S_1 when delta Q_R is heat in a process at Temp T c) position function for an N particle system is given by: Z_n = (z_1)^N = g (m k T/24 h^2)v)^N where g across for single \r\n and Z_1 is single particle partition function and E = 3/2 K_0 TN (for a gas of therefore when a system is heated its Temperature increase the second terms in S