Hess's Law Problems

Calculate $H$ for the reaction: $C_2{H}_{4(g)}+H_{2(g)}{C}_2{H}_{6(g)},$ from the following data.

$C_2{H}_4+H_2{C}_2{H}_6$

$2C{O}_2+3H_{2}O{C}_2{H}_6+3\frac{1}{2}{O}_2$

$H_2+\frac{1}{2}{O}_2{H}_{2}O$

$=-136ks$

$2.$ Calculate $H$ for the reaction $4N{H}_{3(g)}+5O_{2(g)}4N{O}_{(g)}+6H_2{O}_{(g)},$ from the following data.

$N_{2(g)}+O_{2(g)}2NO(g),H=-180\mathrm{.}5kJ$

$N_{2(g)}+3H_{2(g)}2N{H}_{3(g)},H=-91\mathrm{.}8kJ$

$2H_{2(g)}+O_{2(g)}2H_2{O}_{(g)},H=-483\mathrm{.}6kJ$

Calculate $H$ for the reaction $C{H}_{4(g)}+N{H}_{3(g)}HC{N}_{(g)}+3H_{2(g)},$ given:

$N_{2(g)}+3H_{2(g)}2N{H}_{3(g)},H=-91\mathrm{.}8kJ$

$C_{(s)}+2H_{2(g)}C{H}_{4(g)},H=-74\mathrm{.}9kJ$

$H_{2(g)}+2C_{(s)}+N_{2(g)}2HC{N}_{(g)},H=+270\mathrm{.}3kJ$