A stoichiometric combustion of butane C₄H₈ and air results in only half of the C atoms burning to CO; the other half generates CO. This means the products should contain a mixture of H₂O, CO, CO₂, O₂, and N₂, which, after some heat transfer, are at 1000 K. Write the combustion equation with no hydrogen in the products and then use the water–gas reaction to estimate the amount of hydrogen present.