Question
Look at the equation below. It shows the combustion of methane . Calculate the energy released by forming bonds in this reaction. You will need some of the data from the table. Enter your answer as a number kJ/mol CH_(4)+2O_(2)arrow 2H_(2)O+CO_(2) Bond Bond energy (kJ/mol) H-H 436 O=O 498 H-O 464 C-H 413 C=O 803 Nequiv N 945 N-H 391 Cl-Cl 243 H-Cl 432
Answer
4.3
(142 Votes)
Eden
Veteran · Tutor for 12 years
Answer
(4*464) + (2*803)
Explanation
This question is asking for the energy released when bonds are formed in the reaction of methane with oxygen. In other words, this question requires you to calculate the total energy of bond formation and not the bond breaking part. The product side contains four O-H bonds in two water molecules and two C=O bonds in CO2. From the data given in the table, the bond energy of one H-O bond is 464 kJ/mol and that of one C=O bond is 803 kJ/mol. Hence, four H-O bonds would use up 4 times 464 kJ/mol and two C=O bonds would require 2 times 803 kJ/mol. Summing these energies up would give the total energy released in the bond formation.