Consider the balanced chemical equation: 2o3(g) → 3o2(g). how many moles of o2 are produced when 0.50 mol of o3(g) reacts

   2O3→3O2
 The  number  of moles of O2  that  are   produced  when 0.50  moles  of O3(g)  reacted is  0.75  moles

  calculation and explanation

   2  moles    of O3(ozone)  react  to give   3 moles of O2  (oxygen  gas,therefore the reacting   ratio  between O3 :O2 is  2:3

   if 0.50  moles of  O3  reacted  then,by use  of  reacting ratio (2:3)  find the moles of O2  produced

That is   0.50 x3/2  =  0.75   moles

Answerhund's rule;