Physical Chemistry Final Exam Problems Questions and Answers 100% Pass

Physical Chemistry Final Exam Problems Questions and Answers 100% Pass Draw a Carnot cycle diagram and describe the event occurring at each step - I) Reversible Isothermal Expansion II) Reversible Adiabatic Expansion III) Reversible Isothermal Compression IV) Reversible Adiabatic Compression The boiling point of water at a pressure of 50 atm is 538 K. Compare the theoretical efficiencies of a steam engine operating between: 1) The boiling point of water at 1 atm 2) 50 atm, assuming the temperature of the sink to be 308 K - 1) P(1)=1 atm T(C)=308 K T(H)=373 K η=1-(T(C)/T(H)) η=17% 2 | P a g e Author: Katelyn Whitman. ©2025, All Rights Reserved. 2) P=50 atm T(C)=308 K T(H)=538 K η=1-(T(C)/T(H)) η=43% The temperature of 20 L N(2) at 5.00 kPa is increased from 293 K to 673 K at constant volume. Calculate the change in entropy. Assume ideal behavior - V=0.02 m^3 T(1)=293 K T(2)=673 K P=5000 Pa C(V)=20.8 (Diatomic) n=PV/RT ΔS=nC(V)ln(T(2)/T(1)) n= 0.041 mol 3 | P a g e Author: Katelyn Whitman. ©2025, All Rights Reserved. ΔS=0.71 J/K If 1.00 mol N(2) gas expands isothermally from 22.0 L to 44.0 L. What is the entropy change? Assume ideal behavior. - n=1 mol V(1)=22.0 L V(2)=44.0 L ΔS=nRln(V(2)/V(1)) ΔS=5.76 J/K Calculate the change in entropy when 1 mol of a perfect gas expands isothermally to twice its initial volume 1) Reversibly 2) Irreversibly - 1) n=1 mol V(2)/V(1)=2 ΔS=nRln(V(2)/V(1))-nRln(V(2)/V(1)) ΔS= 0 4 | P a g e Author: Katelyn Whitman. ©2025, All Rights Reserved. 2) n=1 mol V(2)/V(1)=2 ΔS=nRln(V(2)/V(1)) ΔS=5.76 J/K Determine the change in entropy when 1 mol of He at 298 K and 1.5 atm expands isothermally to 298 K and 15 atm, then expands isobarically to 100 K and 15 atm. - n=1 mol C(P)=20.8 T(1)=298 K T(2)= 100 K P(1)=1.5 atm P(2)=15 atm ΔS=nC(P)ln(T(2)/T(1))+nRln(P(1)/P(2))