Examples of Chemical Changes
- burning wood
- dissolving salt in water
- mixing acid and base
- digesting food
Examples of Physical Changes
- crumpling a sheet of paper
- melting an ice cube
- casting silver in a mold
- breaking a bottle
How to Tell?Look for an indication that a chemical change occurred. Chemical reactions release or absorb heat or other energy or may produce a gas, odor, color or sound. If you don't see any of these indications, a physical change likely occurred.
In some cases, it may be hard to tell whether a chemical or physical change occurred. For example, when you dissolve sugar in water, a physical change occurs. The form of the sugar changes, but it remains the same chemically (sucrose molecules). However, when you dissolve salt in water the salt dissociates into its ions (from NaCl into Na+ and Cl-) so a chemical change occurs. In both cases a white solid dissolves into a clear liquid and in both cases you can recover the starting material by removing the water, yet the processes are not the same.
Learn More10 Examples of Physical Changes
10 Examples of Chemical Changes
Chemical and Physical Properties
Understanding Chemical and Physical Changes