Question

Consider the following reaction:

A2 + B2 ---> 2AB
ΔH = –365 kJ
The bond energy for A2 is half the amount of AB.
The bond energy of B2 = 447 kJ/mol. What is the bond energy of A2?
a. none of these
b. 812 kJ/mol
c. –183 kJ/mol
d. 630 kJ/mol
e. 271 kJ/mol

Answer 1

The bond energy of A2 is half that of AB, which is derived from ΔH = – 365 kJ for the formation of 2 moles of AB. Calculating the bond energy for one mole of AB as 182.5 kJ, the bond energy for A2 should be 91.25 kJ, thus the answer is 'none of these'.

Step-by-step explanation:

The student asked about the bond energy of A2 given that ΔH for the reaction A2 + B2 → 2AB is –365 kJ, the bond energy of B2 is 447 kJ/mol, and the bond energy for A2 is half the amount of AB. First, we need to find the bond energy of AB by using its relationship with the given ΔH of the reaction. Since the reaction forms 2 moles of AB and releases –365 kJ of energy, we can infer that breaking one mole of AB would require 365/2 = 182.5 kJ of energy.

Since the bond energy of A2 is said to be half that of AB, this means the bond energy of A2 is half of 182.5 kJ, which is 91.25 kJ. However, none of the answer options given match this calculation. Therefore, the correct answer would be none of these.