Question

How much heat is released during the combustion of methane using the given bond dissociation energies: CH4 + 2 O2 → CO2 + 2H2O Number and types of bonds in each molecule: CH4 (4 C-H bonds); O2 (1 O=O); (2 C=O bonds); (2 O-H bonds). Bond dissociation energies: C-C (347 kJ/mol); C-H (413 kJ/mol); O=O (498 kJ/mol; C=O (799 kJ/mol); O-H (467 kJ/mol) Group of answer choices 818 kJ -382 kJ 282 kJ 696 kJ -8181 kJ

Answer 1

The heat released during the combustion of methane is 382 kJ/mol. The heat released during the combustion of methane can be calculated by considering the bond dissociation energies of the bonds involved in the reaction. The total energy required to break the bonds on the reactants side is calculated, as well as the total energy released to form the bonds on the products side. The difference between these two values gives the heat released during the combustion of methane.

Step-by-step explanation:

The given thermochemical equation is:

CH4 + 2 O2 → CO2 + 2H2O + 890.4 kJ

The combustion of 1 mole of methane releases 890.4 kJ of heat energy.

To calculate the heat released during the combustion of methane, we need to consider the bond dissociation energies of the bonds involved:

Energy required to break 4 C-H bonds = 4 x 413 kJ/mol

= 1652 kJ/mol

Energy required to break 1 O=O bond

= 1 x 498 kJ/mol

= 498 kJ/mol

Energy released to form 2 C=O bonds = 2 x 799 kJ/mol

= 1598 kJ/mol

Energy released to form 2 O-H bonds = 2 x 467 kJ/mol

= 934 kJ/mol

The total energy required to break the bonds on the reactants side is 1652 kJ/mol + 498 kJ/mol = 2150 kJ/mol

The total energy released to form the bonds on the products side is 1598 kJ/mol + 934 kJ/mol = 2532 kJ/mol

The heat released during the combustion of methane can be calculated as:

Heat released = Total energy released - Total energy required

= 2532 kJ/mol - 2150 kJ/mol

= 382 kJ/mol

Therefore, the heat released during the combustion of methane is 382 kJ/mol.