The following balanced equation shows the combustion of propane (c3h8).
c3h8 + 5o2 3co2 + 4h2o
according to this equation, how many oxygen atoms are in the final products?
4
6
10
8

              10 Oxygen Atoms

                        The balance chemical equation is as follow is as follow,

                         C₃H₈  +  5 O₂    →    3 CO₂  +  4 H₂O

According to this equation, three molecules of Propane when reacted with 5 molecules of Oxygen (Combustion reaction) produces 3 molecules of Carbon dioxide and four molecules of Water.

Hence, as one molecule of CO₂ contains two oxygen atoms then 3 CO₂ will contain six oxygen atoms. Also, as one molecule of H₂O contains one atom of oxygen then 4 molecules will contain 4 atoms of oxygen. Therefore,

         6 O atoms (CO₂) + 4  Oatoms (H₂O)  = 10 Oxygen atoms in total