Question

AB, A2 and B2 are diatomic molecules. If the bond enthalpies of A2, AB and B2 are in the ratio 1:1:0.5 and enthalpy of formation of AB from A2 and B2 is -100 KJ/mol. What is the bond energy of A2:

Answer 1

Answer:200 KJ

Explanation: here the three compunds are A2 B2 AB. The ratio of formation of these compunds or rather formation of these compund bonds are the energy given by them.

Now if we consider the reaction A2 + B2

-> 2AB

NOW, as the reaction is evident we will see there are 2 A-B bonds and One A-A and B-B each.

Now as the energy ratio of the Bonds given as 1: 1: .5

Let, these energies be x, x and .5x.

Now we will consider the energy required for reactant side will be as one A-A and B-B each are being formed the energy is x+.5x= 1.5x

For the product side we will have for 2 bonds of A-B which will give 2*x energy for product side.

Now the enthalpy of formation is -100 KJ

This means it is endothermic reaction and this means reactant energy is less than product.

Thus 2x - 1.5x = 100 or x= 200

Hence the energies of A2, AB AND B2 ARE 200,200,100

Answer 2

Answer:

Explanation: here the three compunds are A2 B2 AB. The ratio of formation of these compunds or rather formation of these compund bonds are the energy given by them.

Now if we consider the reaction A2 + B2

-> 2AB

NOW, as the reaction is evident we will see there are 2 A-B bonds and One A-A and B-B each.

Now as the energy ratio of the Bonds given as 1: 1: .5

Let, these energies be x, x and .5x.

Now we will consider the energy required for reactant side will be as one A-A and B-B each are being formed the energy is x+.5x= 1.5x

For the product side we will have for 2 bonds of A-B which will give 2*x energy for product side.

Now the enthalpy of formation is -100 KJ

This means it is endothermic reaction and this means reactant energy is less than product.

Thus 2x - 1.5x = 100 or x= 200

Hence the energies of A2, AB AND B2 ARE 200,200,100