Question

If the bonds in the reactants of Figure 7-3 contained 432 kJ of chemical energy and the bonds in the products contained 478 kJ of chemical energy, what would be the amount of energy change during the reaction? Would this energy be absorbed or released? Show your work.

Answer 1

Although the way the curve upon the introduction of chemicals slopes downward it suggests a release, similarly the upward slope of the second picture upon the introduction of chemicals suggests a build up or absorption of said energy.

Since the products have more energy, this reaction is endothermic, meaning heat needs to be added. 

478-432=46kJ of energy absorbed.