When substances undergo changes, they can be categorized

Answer 1

When substances undergo changes, they can be categorized into two main types: physical changes and chemical changes.

1. Physical Changes: These are changes that affect one or more physical properties of a substance without altering its chemical composition. Examples of physical changes include:

   • Changes in state (e.g., melting, freezing, boiling, condensation)
   • Dissolving (e.g., salt in water)
   • Breaking, crushing, or chopping (e.g., cutting a piece of wood)
   • Changes in shape or size (e.g., molding or folding)

2. Chemical Changes: These changes involve a transformation that results in the formation of one or more new substances with different chemical properties. Chemical changes are often characterized by:

   • Color changes (e.g., rusting of iron)
   • Production of gas (e.g., baking soda reacting with vinegar)
   • Formation of a precipitate (e.g., mixing solutions that form a solid)
   • Changes in energy (e.g., heat release or absorption in a reaction)

Understanding these categories helps to analyze and predict the behavior of substances during different processes.