Mole Ratios Within the Conversion

[805132275]

When given a chemical equation like 6 CO2 + 6 H2O → C6H12O6 + 6 O2, the ratio between CO2 and H20 is 1:1. However I have seen in a few post-module questions that it asks about the mass of, perhaps, of O2 when given 3 moles of CO2 and 6 moles of H20. When it says three moles of CO2, do I disregard the stoichiometric coefficient and just use the 3 moles or do I multiply the 6 by 3 to get a total of 18?

[Rebecca Park]

Idk if I completely get your question, but I think you have to find the limiting reactant between CO2 and H20, then whichever one is the limiting reactant (let's say CO2), you would have to multiply the limiting reactant to the ratio of the moles. So mole of O2 (6) would be on the numerator and mole of CO2 (3) would be on the denominator. Then you multiply by the molar mass of O2 & that should give you the answer.

[marcus lin 1E]

So in the case of 3 moles CO2 and 6 moles of H2O, CO2 is the limiting reactant as CO2 and H2O react in a 1:1 ratio. Since the reaction produces an equal number of moles of O2, there will be 3 moles of O2 produced and just multiply that by O2's molar mass to get the grams of O2.

[Nicolette_Canlian_2L]

Just by looking at the equation of a chemical reaction, how can we determine which reactant is limiting?