Question
Why is dissolving salt in water a physical change
Answers
GPT-4o mini
Dissolving salt (sodium chloride, NaCl) in water is considered a physical change because the chemical composition of the salt remains unchanged during the process. When salt is added to water, it dissociates into its constituent ions (sodium ions \(Na^+\) and chloride ions \(Cl^-\)), but the molecular structure of the salt itself does not undergo any chemical transformation.
Here are a few key points that illustrate why it's a physical change:
1. **Reversible Process**: The dissolution of salt in water is reversible. If you evaporate the water, the salt can be recovered in its solid form. This reversibility is a hallmark of physical changes.
2. **No New Substances Formed**: During the dissolution, no new chemical substances are formed. The sodium and chloride ions are still present; they are just separated and distributed in the water.
3. **Physical State Change**: Salt changes from a solid state to being dissolved in a solvent (water), which is a change in physical state rather than a change in chemical identity.
Overall, the process of dissolving salt in water is a clear example of a physical change because it involves a change in state and distribution without altering the chemical identity of the substance.
Here are a few key points that illustrate why it's a physical change:
1. **Reversible Process**: The dissolution of salt in water is reversible. If you evaporate the water, the salt can be recovered in its solid form. This reversibility is a hallmark of physical changes.
2. **No New Substances Formed**: During the dissolution, no new chemical substances are formed. The sodium and chloride ions are still present; they are just separated and distributed in the water.
3. **Physical State Change**: Salt changes from a solid state to being dissolved in a solvent (water), which is a change in physical state rather than a change in chemical identity.
Overall, the process of dissolving salt in water is a clear example of a physical change because it involves a change in state and distribution without altering the chemical identity of the substance.