Electrochemistry

An electrochemical cell is fueled by the combustion of butane at 1 bar and 298 K . Its cell potential is ‌

X

F

×103 volts, where F is the Faraday constant. The value of X is ____ .
Use: Standard Gibbs energies of formation at 298 K are: ∆fGCO2∘=−394kJmol−1;∆fG‌water ‌∘=−237kJmol−1;∆fG‌butane ‌∘=−18kJmol−1