September 27, 2025

What Is The Difference Between A Physical And Chemical Change

Q: Is dissolving salt in water a physical or chemical change?

Dissolving salt in water is a physical change. Although the salt seems to disappear, its chemical structure (NaCl) is unchanged, and the salt can be recovered by evaporating the water.

Q: What are some signs that a chemical change has occurred?

Common signs of a chemical change include a change in color, the production of a gas (bubbling), the formation of a solid (precipitate), or the release or absorption of energy in the form of heat or light.

Learn the key distinction between physical and chemical changes. Understand how physical changes alter form without changing identity, while chemical changes create new substances.

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Physical vs. Chemical Change: The Core Difference

A physical change alters a substance's form, such as its state or shape, but does not change its fundamental chemical identity. In contrast, a chemical change, also known as a chemical reaction, results in the formation of one or more entirely new substances with different properties and chemical compositions.

Simple Examples

An example of a physical change is melting an ice cube into liquid water; it's still H₂O, just in a different state. An example of a chemical change is burning wood; the wood reacts with oxygen to become new substances like ash, carbon dioxide, and water vapor. You cannot get the original wood back.

Frequently Asked Questions

Is dissolving salt in water a physical or chemical change?

What are some signs that a chemical change has occurred?