how will the potentail of the hydrogen/oxygen fuel cell change if the pressure of the gasses was increased from 1 atm to 3 atm
The potential of a hydrogen/oxygen fuel cell is determined by the difference in pressure between the two gases, as well as other factors like temperature and electrode materials. To understand how the potential changes when the pressure is increased from 1 atm to 3 atm, we need to consider the Nernst equation, which relates the cell potential to the concentrations (or partial pressures) of the reactants.
The Nernst equation for a fuel cell is given by:
Ecell = E˚cell - (RT / nF) * ln(Q)
Where:
- Ecell is the cell potential
- E˚cell is the standard cell potential
- R is the gas constant (8.314 J/(mol·K))
- T is the temperature in Kelvin
- n is the number of moles of electrons transferred in the balanced reaction
- F is Faraday's constant (96,485 C/mol)
- Q is the reaction quotient, which depends on the concentrations or partial pressures of the reactants.
In the case of a hydrogen/oxygen fuel cell, the balanced reaction is:
2H2(g) + O2(g) ⟶ 2H2O(l)
Since the reaction involves the stoichiometry of two moles of H2 and one mole of O2, n in the Nernst equation is 2.
When the pressure of the gases is increased, it directly affects the partial pressures (assuming a constant temperature). Therefore, if the pressure of both hydrogen and oxygen gases is increased from 1 atm to 3 atm, the partial pressures in the Nernst equation will change accordingly. However, it is important to note that the actual potential of the fuel cell will depend on other factors such as temperature and the specific characteristics of the cell.
To calculate the exact change in potential, you would need to know the standard cell potential (E˚cell) and the exact partial pressures of hydrogen (PH2) and oxygen (PO2) at the different pressures. Then, using the Nernst equation, you can plug in the values and compute the cell potential for each pressure condition.
Overall, increasing the pressure of the gases will influence the potential of the hydrogen/oxygen fuel cell, and the exact change can be calculated using the Nernst equation and relevant pressure values.