Phosphoric acid, a mild acid used among other things as a rust inhibitor, food additive, and etching agent for cavity repair by dentists, can be made from elemental phosphorus in a two step process. in the first step, phosphorus and oxygen react to form diphosphorus pentoxide: in the second step, diphosphorus pentoxide and water react to form phosphoric acid : suppose the yield of the first step is and the yield of the second step is . calculate the mass of phosphorus required to make of phosphoric acid. be sure your answer has a unit symbol, if needed, and is rounded to significant digits.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-