Question

solutions may be formed through exothermic And endothermic processes. What accounts for this difference?

Answer 1

In a solution ther are two substances, the solute and other substance is the solvent. The following process are followed in the formation of solution:

Process 1: Solute molecules breaks apart from the intramolecular forces holding it together and separate from each        other. This is an endothermic process because energy is required for this reaction, so enthalpy is positive for this process.

deltaH1 > 0

Process 2 : In the second process the solvent molecules separate from each other. The reaction is an endothermic one as energy is required to break the forces between the solution molecules.

deltaH2 > 0

Process 3: During the third process, the separated solute molecules and the separated solvent molecules join together to form a solution. This is an exothermic reaction, because energy is given off as the two substances bond together;

Therefore, delta H3 <0

The total enthalpy of the solution is the sum of delta H1 + delta H2 +delta H3.

If the energy required to break the solvent ans solute molecules are greater than the energy given off during bonding, the solution formation is positive.(Endothermic)

If the energy required to break the solvent and solute molecules is lesser than the energy given off during bonding, the solution formation is negative.(Exothermic)