The balanced chemical reaction is:
2C6H6 + 15O2 → 12CO2 + 6H2O
We
are given the amount of carbon dioxide to be produced for the reaction. This will
be the starting point of our calculations.
42 g CO2 ( 1 mol CO2 / 44.01 g CO2) ( 2 mol C6H6 / 12 mol CO2 ) (78.1074 g C6H6 / 1 mol C6H6) = 12.42 grams of C6H6