* Chemical reactions involve the breaking and forming of bonds: When substances react, the bonds holding their atoms together are broken, and new bonds are formed. This results in a fundamental change in the arrangement of atoms and the way they interact.
* New substances with different properties are created: The products of a chemical reaction are entirely different substances with distinct physical and chemical properties compared to the reactants. For example, the reaction of sodium (a silvery metal) with chlorine gas (a yellow-green gas) produces sodium chloride (table salt), a white crystalline solid with entirely different properties.
* The nature of the atoms is unchanged, but their arrangement changes: While the atoms themselves don't change during a chemical reaction, the way they are connected and arranged does. This rearrangement leads to the formation of new molecules and compounds with unique properties.
Example:
* Burning wood: Wood is made up of complex organic compounds. When burned, these compounds react with oxygen in the air. The bonds within the wood molecules are broken, and new bonds are formed with oxygen, producing ash, carbon dioxide, water, and heat. The ash, carbon dioxide, and water are completely different substances with different properties than the original wood.
Key takeaway: Chemical reactions are fundamentally about transforming substances into new ones with different properties.
