Lead can be prepared from galena (lead II sulfide) by roasting the galena in the presence of oxygen to form lead II oxide and sulfur dioxide. Heating the metal oxide with more galena creates the molten metal and more sulfur dioxide. If we start with 25 mol of PbS, how many moles of SO2 do we create from both steps of the reaction? How many moles of lead do we form? PbS + O2 -> PbO + SO2
PbO + PbS -> Pb + SO2