The net amount of energy absorbed as heat by the solution when a specific amount of solute dissolves in a solvent is called what?

• A. Enthalpy of Solution
• B. Heat of Solution
• C. Solution Energy
• D. Enthalpy Change

Answer: (A)

Think about what happens to energy when a solute dissolves at constant pressure. The heat that the solution absorbs or releases for a given amount of solute is described by the enthalpy of solution. If dissolving absorbs heat, the enthalpy of solution is positive (endothermic); if it releases heat, it is negative (exothermic). This term precisely captures the heat change associated with the dissolution process.

Some sources also call this the heat of solution, but the standard thermodynamic label is enthalpy of solution, which distinguishes it as an enthalpy change specific to dissolution. The broader term enthalpy change would apply to any process, not just dissolution, and “solution energy” isn’t a standard thermodynamic term.