8 g mixture of SiO2 NaCl NH4Cl is being heated in an evaporating dish, NH4Cl sublimes at about 550 oC , the remaining mixture weighs 6.5 grams. Water is added to the remaining mixture and SiO2 is sedimented and dried and weighs 2.5g. What is percentage Composition of the mixture

  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-

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