Please help I have been stuck on this problem for a couple hours and can't figure it out

11.92 Liters O₂(g) at STP

Explanation:

For most stoichiometry problems, if one will convert all given data into moles, solve by rxn ratios, then finish by converting to needed dimensions to complete problem.

2Pb(NO₃)₂ => 2PbO + 4NO₂ + O₂

Given 237.5 grams PbO formed in reaction = 237.5 g/223.2 g/mole = 1.064 mole PbO

From equation ratios, moles O₂ formed = 1/2(moles PbO) = 1/2(1.064 moles O₂) = 0.532 mole O₂

0.532 mole O₂ = 0.532 mole x 22.4  liters/mole at STP = 11.91756272 liters (calculator answer) ≅ 11.92 liters O₂ at STP (4 sig.figs. based on given 237.5g PbO)