The balanced chemical equation for the reaction between butane (C4H10) and oxygen is:
2 C4H10 (g) + 13 O2 (g) → 8 CO2 (g) + 10 H2O (g)
We can interpret this to mean:
2 moles of butane (C4H10) and
mole(s) of oxygen
React to produce:
mole(s) of carbon dioxide and
mole(s) of water