How much energy is evolved during the reaction of 51.2 g of al, according to the reaction below? assume that there is excess fe2o3. fe2o3(s) + 2 al(s) â al2o3(s) + 2 fe(s) î´hâ°rxn = -852 kj?

Answer : The amount of energy evolved during the reaction is, .

Solution : Given,

Mass of Al = 51.2 g

Molar mass of Al = 27 g/mole

First we have to calculate the moles of Al.

The balanced combustion reaction is,

From the given reaction, we conclude that

As, 2 moles of Al evolved energy =

So, 1.896 moles of Al evolved energy =

Therefore, the amount of energy evolved during the reaction is, .

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.