Chapter 9, Problem 9.120SP

Use the average bond dissociation energies in Table 9.3 to calculate approximate reaction enthalpies in kilojoules for the following processes:
(a) $2C{H}_4\left(g\right)\to C_2{H}_6\left(g\right)+H_2\left(g\right)$
(b) $C_2{H}_6\left(g\right)+F_2\left(g\right)\to C_2{H}_{5}F\left(g\right)+HF\left(g\right)$
(c) $N_2\left(g\right)+3H_3\left(g\right)\to 2N{H}_3\left(g\right)$