In the reaction #2CO(g) + O_2(g) -> 2CO_2(g)#, what is the ratio of moles of oxygen used to moles of #CO_2# produced?
Why the ratio of dioxygen to carbon dioxide is
You have given the stoichiometric equation, which states UNEQUIVOCALLY that 2 mole of carbon monoxide reacts with 1 mole of dioxygen gas to give 2 mole of carbon dioxide. We could also state that 1 volume of carbon monoxide, and 2 volumes of dioxygen, react to give 2 volumes of carbon dioxide.
Look at the stoichiometry of the reaction. One mole of dioxygen reacts with 2 moles of carbon monoxide to give 2 moles of carbon dioxide. Because products and reactants are conceived to hold identical temperatures, and pressure is constant, one VOLUME of dioxygen reacts with 2 VOLUMES of carbon monoxide to give 2 VOLUMES of carbon dioxide.
First check to see if the equation is balanced. It is so now let's find the ratio.
The ratio is the stoichiomeric coefficient of the element or compound.
Oxygen: Carbon dioxide