Key Idea.
Section 1
Evidence of Change
How do we know a chemical reaction occurred? We look for new properties. Signs include a distinct color change, the production of a gas (bubbles), or the formation of a solid precipitate from liquids.
These observable signs provide evidence that new substances are being formed, distinguishing a chemical reaction from a simple physical change like melting or mixing.
Section 2
Reactants to Products
A chemical reaction is a transformation process. The starting substances are called reactants, and the ending substances are called products.
Unlike a physical mixture where ingredients can be separated easily, a chemical reaction creates new materials that cannot be turned back into reactants by simple physical means.
Expand to review the lesson summary and core properties.
Section 1
Evidence of Change
How do we know a chemical reaction occurred? We look for new properties. Signs include a distinct color change, the production of a gas (bubbles), or the formation of a solid precipitate from liquids.
These observable signs provide evidence that new substances are being formed, distinguishing a chemical reaction from a simple physical change like melting or mixing.
Section 2
Reactants to Products
A chemical reaction is a transformation process. The starting substances are called reactants, and the ending substances are called products.
Unlike a physical mixture where ingredients can be separated easily, a chemical reaction creates new materials that cannot be turned back into reactants by simple physical means.