Question

Calculate AH® for the reaction using the given bond dissociation energies. CH, (g) +202(9) — CO2(g) + 2 H2O(g) Bond AH° (kJ/mol) 0-0 | 142 H-0 459 C-H 411 C=0 799 O=0 498 C-0 358 This reaction is kJ/mol AH° = O endothermic. O exothermic.

Answer 1

If a bond is breaked then energy is given.

Energy is released if bond is formed.

∆H = - 794kJ/mol.

As ∆H is negative so the reaction is exothermic.

Ону о + 20, у со страна an a bond is formed energy is released. If we break a bond then energy is given nes 0=C =0 2x c=0 = – 2 x 799 kJ/ mol =-1598 kJ/mol H =-2xo-H -2x 459 kJ/mot - - 918 kJ/mol 2 molecules of Ho are = - 2x918 kJ/mol -foomed - 1836 kJ/mol Bonds breaked; 4x CH = 4x4 11kJ/mol → 1644 Kilmol 0=0 498kJ/mol Imolecules of gruas a 996 kJ/mol 0 0 = 2x400 - backend

DH=(-1598 - 1836 + 1644 +996) kJ/mol = -794 kJ/mol.