[mala06]

a sample of an unknown oxide of barium gave upon exhaustive heating 5 gm of pure Bao and 366 cc of oxygen gas measured at 273 k and 1 atm pressure.what is the emperical formula of the unnown oxide? what wt of oxide was present initially?
here i did the following:-
mole of barium=(366/1000/22.4)=0.01633
mole of oxygen=2*(mole of o₂ )+mole of oxygen in barium
=0.03268+0.01633=0.4901
and their ratio (emperical formula)is 1:3
but here answer is 1:2
so what mistake did i make?

[Hunter2]

Check your moles of oxygen again.  How much is delivered from BaO and from the O₂