Final answer:
The enthalpy change (∆Hrxn) for the reaction CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g) can be calculated using bond energies. By accounting for the bonds being broken and formed in the reaction, the enthalpy change can be determined. Based on the given bond energies, the enthalpy change for the reaction is -802 kJ/mol, indicating an exothermic reaction.
Step-by-step explanation:
The enthalpy change, ∆Hrxn, for the reaction
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
can be calculated by using bond energies. To calculate ∆Hrxn, the bond energies of the bonds being broken and formed must be taken into account. In this reaction, one C-H bond and four Cl-Cl bonds are broken, and four C-Cl bonds and four H-Cl bonds are formed.
The bond energies are as follows:
- C-H = 413 kJ/mol
- Cl-Cl = 242 kJ/mol
- C-Cl = 328 kJ/mol
- H-Cl = 432 kJ/mol
Using the bond energies, the calculation is as follows:
(ΣBonds Broken) - (ΣBonds Formed)
(1 x 413) + (4 x 242) - (4 x 328) - (4 x 432) = -802 kJ/mol
Therefore, the enthalpy change for the reaction is -802 kJ/mol. The negative sign indicates that the reaction is exothermic.