Ch4(g) + h2o(g) 3h2(g) + co(g) enthalpy of formation of CH4

Kc=[[CO][H2]3[CH4][H2O]

3.90=(0.30)(0.10)3[CH4]×0.02

[CH4]=0.023.90×0.30×(0.10)3=5.85×10−2 M

Thus, the concentration of methane in the mixture is 5.85×10−2 M.

  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-

thats how its supposed to be