Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Homework Help
Biology and Chemistry Homework Help
Calculation of Helmholtz energy
Reply to thread
Message
[QUOTE="Youngster, post: 4513239, member: 400437"] [h2]Homework Statement [/h2] The 4 fundamental equations of thermodynamics are: [I]dE = TdS - PdV dH = TdS + VdP dG = VdP - SdT dA = - PdV - SdT[/I] Supose a gas obeys the equation of state P = [itex]\frac{nRT}{V}[/itex] - [itex]\frac{an^{2}}{V^{2}}[/itex] Use one of the fundamental equations to find the change in Helmholtz energy (A) when one mole of gas expands isothermally from 20 L to 40 L at 300 K. Let a = 0.1 Pa m[SUP]6[/SUP] mol[SUP]-2[/SUP]. (1 L = 10[SUP]-3[/SUP] m[SUP]3[/SUP]). [h2]Homework Equations[/h2] Well the four fundamental equations should be a given. In particular, the fourth one for Helmholtz energy dA. [h2]The Attempt at a Solution[/h2] Well I tried integrating the fourth fundamental equation [itex]\int[/itex]dA = -[itex]\int[/itex]PdV -[itex]\int[/itex]SdT And since the process is isothermal, the last term is zero, and the Helmholtz energy is just the product of the pressure P and the change in volume ΔV. But how would I obtain the pressure P? My first guess would be to plug in the known values into the equation of state: P = [itex]\frac{nRT}{V}[/itex] - [itex]\frac{an^{2}}{V^{2}}[/itex] I'm letting R = 8.314 [itex]\frac{Pa m^{3}}{K mol}[/itex] since that would lead to a dimensionally correct answer in Pa. [B]My problem is what to plug in for volume considering I have two values.[/B] [/QUOTE]
Insert quotes…
Post reply
Forums
Homework Help
Biology and Chemistry Homework Help
Calculation of Helmholtz energy
Back
Top