Question

calculate the value of δh° for the reaction c2h6 2 cl2 → c2h4cl2 2 hcl given the bond energies (kj/mol):

Answer 1

The δH° for the reaction C2H6 + 2Cl2 → C2H4Cl2 + 2HCl is -428 kJ/mol.

Step-by-step explanation:

To calculate the δH° for the reaction C2H6 + 2Cl2 → C2H4Cl2 + 2HCl, we need to consider the bond energies involved. One mole of H-H bonds needs to be broken, which requires 436 kJ/mol of energy. One mole of Cl-Cl bonds also needs to be broken, which requires 243 kJ/mol of energy. On the product side, two moles of H-Cl bonds are formed, releasing a total of 864 kJ/mol of energy. Since the bonds in the products are stronger than those in the reactants, the reaction releases more energy than it consumes. The δH° for the reaction is therefore -428 kJ/mol.

Answer 2

To calculate δH° for the reaction, the energy needed to break bonds in reactants is subtracted from the energy released when new bonds in the products are formed. This is demonstrated with the formation of HCl, but the bond energies for C2H6 and others involved in the full reaction were not provided.

Step-by-step explanation:

To calculate the value of δH° for the reaction C2H6 + 2 Cl2 → C2H4Cl2 + 2 HCl, you would need to know the bond energies for each type of bond being broken and formed during the reaction. However, these have not been provided for all the relevant bonds in this reaction. To calculate δH°, you would use the given bond energies to sum the energy required to break bonds in the reactants and subtract the energy released when bonds in the products are formed.

The general formula for calculating δH° based on bond energies is:

δH° = Σ (bond energies of bonds broken) - Σ (bond energies of bonds formed).

Based on the information provided, we can look at the formation of HCl. We can apply the information given that the bond energy for the H-H bond is 436 kJ/mol and for the Cl-Cl bond is 243 kJ/mol. Thus, forming 1 mole of HCl will release 864 kJ of energy. If we had the bond energies for the other bonds in the reaction, we could use this approach comprehensively to calculate δH° for the entire reaction.