Calculate the percent composition by mass of each element in Al(OH)3. Use at least three significant figures. Al =

0=

H=

nope nope nope nope nope nope nope nope

Al= (27/78)x100

Al= 34.6%

O= (48/78)x100

O= 61.5%

H= (3/78)x100

H= 3.85%

  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-