Predict products or c3h8 + o2 via combustion

When propane   is  burned  in  air  in  a process  known  as  combustion  it  produce   carbon  (IV) oxide  and  water
 the  word  equation  is  as follows,
  propane + oxygen--->carbon (IV)  oxide + water
chemical  equation  is  as follows
  2C3H8  +7O2--->  3CO2  + 8 H2O
hence  2 moles  of propane  reacted with 7  moles  of  oxygen  to  give 3  moles of  CO2  and  8  moles  of  H2o

The correct answer is "atomic weight".