In the following reaction, how many liters of oxygen will produce 15.67 liters of CO2 at STP? C2H4(g)+ 3O2(g) 2CO2(g) + 2H2O(g)

5.22 liters
7.84 liters
10.45 liters
23.50 liters
88.00 liters

Respuesta :

We solve for the number of mols of CO2 given its volume, assuming that it is an ideal gas. 
                         n = PV / RT
Substituting,
                         n = (1 atm)(15.67 L) / (0.082 L.atm/mol.K)(273.15 K) = 0.7 moles
From the balanced chemical reaction above, we determine the number of O2 moles needed to produce 0.7 moles CO2.
           0.7 moles CO2 x (3 moles O2/ 2 moles CO2) = 1.05 moles O2
Then, we multiply this value by 22.4 L/mol
                              1.05 moles O2 x (22.4 L / mol) = 23.52 L O2
Thus, the answer is the fourth choice.