Transformations All Around Us

Chemical reactions occur when substances interact to form new substances with different properties. During a reaction, atoms are rearranged, but the total number of atoms remains the same (thanks to the Law of Conservation of Mass).

Types of Chemical Reactions

• Synthesis: Two or more substances combine to form a new compound.
• Decomposition: One compound breaks down into simpler substances.
• Single Replacement: An element replaces another in a compound.
• Double Replacement: Two compounds exchange ions to form new compounds.
• Combustion: A substance, usually containing carbon, reacts with oxygen to produce energy, carbon dioxide, and water.

Indicators of Chemical Change

• Color change
• Gas production (bubbles)
• Temperature change
• Formation of a precipitate (solid)

Real-world Impact

Chemical reactions power our bodies, fuel cars, and allow us to cook delicious food!