Complete the balanced equation for the overall reaction in a hydrogen fuel cell. _ H2 + ___ > _ H2O

Hydrogen fuel cells are really important as they can be used to power electrical cars, so it's something that a lot of scientists are looking into at the moment. We need to balance this equation, so we need the same amount of things at the begining, in the reactants, as we do at the end, in the products. We have that Hydrogen (H₂) and something are making water (H₂O), so the thing that is in the product that isn't in the reactants is Oxygen (O₂). This gives us _H₂ + _ O₂ > _H₂O, so now we need to make sure we have the same amount of each element in the reactants and products. If you tally up the number of H and O at the start and the end you see we need more oxygens in the product. Overall we have 2H₂ + O₂ > 2H₂O