Chemical and Physical Changes

• A physical change is a change in a substance that does not change its identity, such as a change of state.
• Matter can change state when it loses or gains thermal energy.
• Freezing, melting, and boiling are all examples of changes of state.
• Some other physical changes include breaking, tearing, cutting, or crushing.
• A physical change is only a change in appearance, not chemical identity.
• A chemical change is a change in which one or more substances combine or break apart to form new substances.
• Whenever a chemical change (or reaction) occurs, a new substance is ALWAYS formed.
• Some common examples of chemical changes are rusting, tarnishing, cooking, burning, and sugar caramelizing.