3. Calculate the mass of oxygen produced from the decomposition of 75.0 g of potassium chlorate.
2KClO3(s)  2KCl(s) + 3O2(g)

29.3 grams

Explanation:

2KClO3 - > 2 KCl + 3O2

Moles of KClO3=75. g/123 g/mol=0.610 mol

Moles of O2 =0.610 mol* 3/2=0.915 mol

Mass of oxygen = 0.915 mol x 32 g/mol=29.3 g

whats the meaning of /

  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-