Question

if you produce 5.7 of H2O, how many liters of O2 will be required?

Answer 1

5.7 what?
from what reaction?
what conditions?
I'll assume that is 5.7L H2O, then
assume rxn is
2H2 + O2 ==> 2H2O
and assume this is at STP.
5.7 L H2O x (1 mol O2/2 mols H2O) = 5.7 x 1/2 = ? L O2