Calculate Delta H for the reaction SolutionCH4g NH3g HCNg

Solution

CH4(g) + NH3(g) --> HCN(g) + 3H2(g)

N2(g) +3 H2(g) ---> 2 NH3(g) ?H= -91.8 kJ... ..for 1 mole NH3 = -45.9kJ

C(s) + 2 H2(g) ---> CH4(g) ?H = -74.9 kJ

H2(g) + 2 C(s) + N2(g) ---> 2 HCN(g) ?H=+270.3 kJ.... .for 1 mole HCN, = 135.15kJ

?Hrxn = the sum of the heats of formation products - sum of the heats of formation reactants

?H = (-45.9) - (-74.9 + 135.15) = -106.15kJ

?H =-106.15kJ