* Elements: Basic building blocks of matter, like carbon, hydrogen, oxygen, etc.
* Chemically bonded: The atoms of different elements are held together by forces called chemical bonds.
* Fixed ratio: The elements are always present in the same proportion in a given compound.
Examples of Single Compounds:
* Water (H₂O): Two hydrogen atoms bonded to one oxygen atom.
* Sodium chloride (NaCl): One sodium atom bonded to one chlorine atom.
* Carbon dioxide (CO₂): One carbon atom bonded to two oxygen atoms.
* Glucose (C₆H₁₂O₆): Six carbon atoms, twelve hydrogen atoms, and six oxygen atoms bonded in a specific arrangement.
Key Points:
* Pure substances: Compounds are considered pure substances, meaning they have a uniform composition throughout.
* Distinct properties: Compounds have unique properties that are different from the elements that make them up. For example, water is a liquid at room temperature, while hydrogen and oxygen are gases.
Contrast with Mixtures:
Unlike mixtures, where different substances are physically combined, compounds are formed through chemical reactions that create new substances with different properties.
