Determine the standard heat of each of the following reactions at the given temperature:

$($a$)H_2{S}_{(g)}+2H_2{O}_{(g)}3H_{2(g)}+S{O}_{2(g)}$

at $850K$

$($b$)N_{2(g)}+C_2{H}_2(g)2HC{N}_{(g)}$

at $650K$

$($c$)C{H}_{4(g)}+2H_2{O}_{(g)}C{O}_{2(g)}+4H_{2(g)}$

at $980K$