Question

Use bond energies to calculate the energy change for this reaction.

Bond and Energy (kJ/mol)
H-H = 436
Br-Br = 194
H-Br = 366
C-H = 410
C-Br = 270

Answer 1

To find the energy change for a reaction, sum the bond dissociation energies for the reactants and subtract the energy released from bond formation in the products. For instance, breaking H-H and Br-Br requires a certain amount of energy, while forming H-Br bonds releases energy.

Step-by-step explanation:

To calculate the energy change for the reaction using bond energies, you would first determine the total energy required to break the bonds in the reactants (bond dissociation energies) and then calculate the total energy released when the bonds in the products are formed.

Step 1: Reactant Bond Dissociation Energies

• H-H bonds: 436 kJ/mol
• Br-Br bonds: 194 kJ/mol

We would add these values to find the total energy needed to break the bonds on the reactant side.

Step 2: Products Bond Formation Energies

• two H-Br bonds: 366 kJ/mol each, totaling 732 kJ/mol for two

Now, subtract the energy of bond formation from the energy used to break the bonds to find the overall energy change for the reaction.