Question

1. most changes can be clearly defined as physical or chemical. dissolving is more difficult to classify. why? (p. 6)

Explanation:

Dissolving can involve both physical (e.g., dispersion of solute particles in solvent) and chemical aspects (e.g., formation of new species like solvated ions in some cases). For example, when NaCl dissolves in water, the ionic lattice breaks (physical - change in state of the solid) and ions are solvated (can be seen as a chemical - like interaction between ions and water molecules). So it's not purely one type of change.

Answer:

Dissolving can have characteristics of both physical (e.g., change in state of solute) and chemical (e.g., interaction between solute and solvent) changes, so it's hard to classify as purely physical or chemical.