University:
The Pennsylvania State University
Course:
CHEM 450 | Thermodynamics
Academic year:

2024
Views:

407

Pages:

2
Author:

Alexis H.

Problem Set #25 Assigned: March 1, 2024 Due: March 11, 2024 at 2:30 pm 1. Suppose that 2.5 mmol of a perfect gas initially occupies 42 cm3 at 300 K. It is then expanded isothermally to 600 cm3. Calculate G for this process. 2. The change in the Gibbs energy of a constant-pressure process varies as G = -85.40 J + (36.5 J/K)(T). What is S for this process? 3. The change in Gibbs energy for a constant pressure process varies as G = -85.40 J + (36.5 J/K)(T). Find H for this process. 4. (a) Estimate the change in the Gibbs energy of 1.00 L of liquid octane when the pressure on it is increased from 1.00 atm to 100 atm at constant temperature. (b) Given that the mass density of octane is 0.703 g/cm3, find the change in the molar Gibbs energy. 5. Calculate the change in the molar Gibbs energy for a perfect gas when its pressure is increased isothermally from 1.00 atm to 100 atm at 298 K. 6. (a) Integrate the Gibbs – Helmholtz equation between Ti and Tf to find an equation for Gf at a temperature, Tf, when the initial value is Gi at a temperature Ti. You may assume that H is a constant. 7. Use the equation you generated in question #6 to find G(Tf) if G(Ti) = -21.0 kJ. Ti = 298 K, Tf = 310 K and H = 31 kJ. 1 2 ΔG ΔH TLS ΔG 85.40J 36.54K T dG Vdp DG BT dp Δ5 36.5 K ΔG NRT 3 ΔG ΔH TLS ΔG nRTIn ΔG pat ΔH 85.40J ΔG ARTIn ΔG 2.5 103mol 85.40J 36.54K T 8.314J kmol 300k In 6 4 3 ΔG 16.58J 4 a dG Vdp Sdt AT 0 dG Vdp b mass 1000 0.703 703 g mass moles molarmass molargibbsenergy 703 114.23 6 15moles 10 SdG JVdp molargibbsenergy ΔG V p p ΔG IL 1631.17 J mo 100atm latm 99L atm ΔG 10031.67J 101.33 Latm 5 dG Vdp 6 86 ΔH dp SAG ΔGf Tf ΔG NRT ΔG ARTin 1 8.314 298 in ΔG 11KJ Mol 7 1567 Δ ΔGfTf 31 23.09 0 8 ΔG Ti