Practice question · Numerical answer
A system at 300 K has internal energy 2000 J and entropy 4.0 J/K. Compute its Helmholtz free energy in J.
Hints
- Helmholtz energy is internal energy minus temperature times entropy.
- Compute 2000 - 300 x 4.0.
Show the answer
800 (answers within ±10 count)
Why
J. Of the 2000 J stored, only 800 J is extractable as work at this temperature, the remaining 1200 J must be paid to the surroundings as heat.
Practise Thermodynamic Potentials and Maxwell Relations
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