Dissolving Sugar in Water: A Physical Change
Dissolving sugar in water is classified as a physical change due to the following reasons:

1. No Chemical Alteration
- The chemical structure of sugar (sucrose) remains unchanged during the dissolution process.
- The molecular composition, which is C12H22O11, does not alter, indicating no new substances are formed.

2. Reversibility
- The process is reversible. Evaporating the water will leave behind the sugar, allowing it to be recovered in its original form.
- This characteristic is a hallmark of physical changes, which can often be undone.

3. Changes in Physical State
- Sugar transitions from a solid state to a solute dispersed within the liquid state of water.
- This alteration in state does not involve any change in the identity of the sugar.

4. Energy Changes
- The dissolution process involves energy changes, primarily in the form of heat, but these changes do not involve breaking or forming chemical bonds.
- The interactions between water molecules and sugar molecules are physical interactions rather than chemical reactions.

5. Observational Evidence
- The resulting solution appears clear and homogeneous, demonstrating that the sugar is uniformly distributed within the water.
- The properties of the sugar solution differ from those of the individual components, yet the components retain their original properties once separated.
In summary, the process of dissolving sugar in water exemplifies a physical change, characterized by the retention of chemical identity, reversibility, and alterations in physical state.