Use the molar bond enthalpy data in the table to estimate the value of Δ𝐻∘rxn for the equation C2H4(g)+HBr(g)⟶C2H5Br(g)

Question

I am not sure how to upload a picture of the bond energy table.

Answer 1

Without the table, we can't give you a precise answer, but I will attempt to explain how to do this using the table you have.

Find the total bond energy of the reactants

1 C=C bond

4 C-H bonds

1 H-Br bond

add them up to get bond energy in the reactants

Find the total bond energy of the products

1 C-C bond

5 C-H bonds

1 C-Br bond

add them up to get bond energy in the products

Since it takes energy to break bonds (reactants) this will be a positive value, and energy is liberated when bonds are formed (products), this will be a negative value. The difference is the ∆Hºrxn. Hope that makes sense.