A student mixes 2 chemicals in a flask and notices that the flask starts to feel cold. Explain this change in terms of the total bond energy.

Answer 1

When two chemicals are mixed, a chemical reaction may occur. During a chemical reaction, bonds between atoms are broken and new bonds are formed. Breaking bonds requires energy, while forming bonds releases energy. If the energy released during bond formation is greater than the energy required to break the bonds, the reaction is exothermic and heat is released. Conversely, if the energy required to break the bonds is greater than the energy released during bond formation, the reaction is endothermic and heat is absorbed.

In this case, the fact that the flask feels cold indicates that the reaction is endothermic and heat is being absorbed. This means that the energy required to break the bonds between the two chemicals is greater than the energy released during bond formation. Therefore, the total bond energy of the products is higher than the total bond energy of the reactants.