AP Chemistry Flashcards: Free Energy of Dissolution
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
What are the three main energetic factors that contribute to the overall ΔG° of dissolution?
The three factors are the energy involved in breaking the solid's interactions, reorganizing the solvent, and the interaction of the dissolved species with the solvent.
Card 1 of 10
All Flashcards (10)
What are the three main energetic factors that contribute to the overall ΔG° of dissolution?
The three factors are the energy involved in breaking the solid's interactions, reorganizing the solvent, and the interaction of the dissolved species with the solvent.
If a salt's dissolution is endothermic (ΔH > 0) but spontaneous (ΔG < 0), what must be true about the entropy change (ΔS)?
The entropy change (ΔS) must be positive and large enough to overcome the unfavorable enthalpy change, driving the overall process to be spontaneous.
If the energy released from solute-solvent interactions is much larger than the energy required to break solute-solute and solvent-solvent bonds, how would this affect the enthalpy of dissolution (ΔH)?
This scenario would result in a net release of energy, making the overall enthalpy of dissolution (ΔH) negative, meaning the process is exothermic.
What energetic change must the solvent undergo during dissolution?
The solvent must undergo reorganization, which involves breaking some solvent-solvent interactions to create space for the dissolved solute particles.
Explain the overall relationship between enthalpy, entropy, and the solubility of a salt.
The solubility of a salt depends on the balance between the enthalpy change (ΔH) and entropy change (ΔS), as these two factors together determine the overall free energy change (ΔG).
Why is it often difficult to predict the total ΔG° for a dissolution process?
Predicting the total ΔG° is challenging because it results from multiple energetic factors (related to solute, solvent, and their interaction) which can cancel each other out.
What two thermodynamic quantities determine the free energy change (ΔG°) for the dissolution process?
The free energy change for dissolution is determined by the changes in enthalpy (ΔH) and entropy (ΔS) that occur during the process.
What does the 'interaction of the dissolved species with the solvent' factor refer to?
This refers to the formation of new attractive forces between the dissolved solute particles (ions or molecules) and the surrounding solvent molecules.
What does the 'breaking the solid's interactions' factor in dissolution refer to?
This factor refers to the energy required to overcome the attractive forces holding the ions or molecules together in the solid crystal lattice.
How is the solubility of a salt related to the free energy change (ΔG°) of dissolution?
The solubility of a salt is directly related to the spontaneity of its dissolution; a negative ΔG° indicates a spontaneous process and thus a soluble salt.