Question

A fuel cell car runs on hydrogen produced from steam-methane reforming reaction. The efficiency of the fuel cell is 55% and at voltage is 0.75 V. What is the total direct or indirect CO2 production for a trip that consumes 4 kg of hydrogen? O 8kg O 0.4 kg o 22 kg 108 kg

Answer 1

In fuel cell the reactio takes place as follows

anode reaction CH₄ + H₂O -------> CO₂ + 8H⁺ + 8 e^-

Cathode reaction 4O₂ + 8H⁺ + 8 e^- ---------> 4H₂O

Overall reaction CH₄ + 2O₂ -----------> CO₂ + 2H₂O

So, from here it is clear that 1 mole of CH₄ produces 8 moles of Hydrogen

So, molar mass of H = 1 g/ mol

no. of moles of H present = given mass/ molar mass = 4000 g/1 g = 4000 moles

So, no. of moles of CH₄ present = 500 moles

molar mass of CH₄ = 16 g/mol

So 500 moles = 500 moles * 16 g/moles = 8000 g = 8 kg