Question

Consider the following reaction: a₂ b₂ → 2ab, δh = –325 kj the bond energy for a₂ is half the amount of ab. the bond energy of b₂ = 415 kj/mol. what is the bond energy of a₂?

A) 205 kJ/mol
B) 245 kJ/mol
C) 325 kJ/mol
D) 415 kJ/mol

Answer 1

The bond energy for A₂, given that it's half of AB's bond energy, is calculated from the enthalpy change ΔH. It is found to be 81.25 kJ/mol based on the given values, but this result is missing in the options provided suggesting a possible error in the information presented.

Step-by-step explanation:

We are given that the reaction A₂ B₂ → 2AB has a change in enthalpy (ΔH) of –325 kJ and that the bond energy for A₂ is half that of AB. Additionally, the bond energy for B₂ is given as 415 kJ/mol. To find the bond energy for A₂, we need to use the information that the energy of bond A₂ is half of AB's bond energy.

Since the energy released (ΔH) when forming 2 moles of AB is –325 kJ, the bond energy of one mole of AB would be half of this value. Hence, the bond energy for AB is –325 kJ / 2 = –162.5 kJ. Now, the bond energy for A₂, being half of AB, would be –162.5 kJ / 2 = –81.25 kJ. However, bond energies are conventionally expressed as positive values, so we consider the absolute value, which gives us the bond energy of A₂ as 81.25 kJ/mol. This is not one of the options provided, which suggests there may be an error in the options or the question as presented.