Question

Use the table to answer the question.

Bond Energies Involved in the Reaction of Methane with Chlorine
Reaction CH4 + 4Cl2 → CCl4 + 4HCl
Reactants Products
–C


4 Cl–Cl

4 C–Cl

4 H–Cl

Energy of Bonds Broken (Reactants) / Formed (Products)
4 × 411 kJ/mol

4 × 242 kJ/mol

4 × 327 kJ/mol

4 × 427 kJ/mol

Which statement about the change in bond energy of this reaction is correct?

(1 point)

The reaction is endothermic because the total bond energy of the reactants is greater than the total bond energy of the products.

The reaction is exothermic because the total bond energy of the reactants is less than the total bond energy of the products.

The reaction is endothermic because the energy of each bond in the reactants is less than the energy of a bond in the products.

The reaction is exothermic because the energy of each bond in the reactants is greater than the energy of a bond in the products.

Answer 1

Calculate totals:

- Bonds broken (reactants): 4×411 + 4×242 = 4×(411+242) = 4×653 = 2612 kJ/mol
- Bonds formed (products): 4×327 + 4×427 = 4×(327+427) = 4×754 = 3016 kJ/mol

Since more energy is released forming the product bonds than is required to break the reactant bonds, the reaction is exothermic. Correct choice: The reaction is exothermic because the total bond energy of the reactants is less than the total bond energy of the products.