* Physical Change: Involves a change in the form or appearance of a substance, but not its chemical composition.
* Chemical Change: Involves the formation of new substances with different chemical properties.
When NaCl dissolves in water:
* The ionic bonds holding the sodium (Na+) and chloride (Cl-) ions together in the crystal lattice are broken.
* The ions become surrounded by water molecules, a process called hydration.
* The ions are now dispersed throughout the water, forming a homogeneous solution.
Key Points:
* No new substances are formed: NaCl is still present in the solution, just in a dissolved form.
* The chemical composition of both NaCl and water remains unchanged.
* The change is reversible: You can recover the solid NaCl by evaporating the water.
Therefore, dissolving NaCl in water is a physical change because it involves a change in state and the separation of ions, but not the formation of new substances.
