Impact of Temperature on Fuel Cell Work Output

Click For Summary
SUMMARY

The discussion centers on the impact of temperature on the maximum work output of a fuel cell reaction represented by the equation 2 H2(g) + O2(g) → 2 H2O(l) with an equilibrium constant K = 1.28e83. Participants concluded that as temperature increases, the maximum work output (w_max) decreases due to the relationship established by the Gibbs free energy equation (G = -RTln(K)). Specifically, since both the enthalpy change (dH) and entropy change (dS) are negative, the work output becomes more negative with increasing temperature, indicating a decrease in usable work.

PREREQUISITES
  • Understanding of Gibbs free energy and its equations
  • Familiarity with thermodynamic concepts such as enthalpy (dH) and entropy (dS)
  • Knowledge of chemical equilibrium and the significance of the equilibrium constant (K)
  • Basic principles of fuel cell operation and thermodynamics
NEXT STEPS
  • Study the relationship between temperature and Gibbs free energy in detail
  • Explore the implications of negative enthalpy and entropy changes on chemical reactions
  • Learn about the thermodynamic efficiency of fuel cells at varying temperatures
  • Investigate advanced fuel cell technologies and their performance metrics
USEFUL FOR

Students and professionals in chemistry, chemical engineering, and energy systems who are interested in thermodynamics and fuel cell technology.

eraemia
Messages
53
Reaction score
0

Homework Statement



2 H2(g) + O2(g) 2 H2O(l) K = 1.28e83

As temperature increases, does the maximum amount of work obtained from the fuel cell reaction increase, decrease, or remain the same?

Homework Equations



1. G = -RTln(K)
2. dG = dH - tdS
3. w_max = dG

The Attempt at a Solution



Okay, using formation values, I calculated that for this reaction, both dH and dS are < 0.

If dG = w_max (eq. 3), then w_max = -RT ln K (1 and 3)
Since ln(K) is positive, the larger the T, the more negative w_max.
Thus, as T increases, w_work decreases?

Is that right? Thanks.
 
Physics news on Phys.org
eraemia said:
Thus, as T increases, w_work decreases?

Is that right? Thanks.
Sounds good.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
1
Views
3K
Replies
1
Views
2K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 2 ·
Replies
2
Views
18K