Pure Substances

• Definition: Pure substances are materials that have a uniform and definite composition. They cannot be separated into different components by physical means.

• Examples: Elements like oxygen and compounds like water are considered pure substances.

Elements: composed of a single atom type,

Example - hydrogen (H), helium (He), and carbon (C), which cannot be broken down into simpler substances by chemical means.

Compound: composed of two or more atoms chemically bonded together,

Example - sodium chloride (NaCl) and carbon dioxide (CO_2), which can be broken down into simpler substances through chemical reactions. .

Pure substance: uniform and definite.

Example - coffee, water and salt. A; elements B:compounds.

{CANNOT BE SEPERATED BY PHISICAL MEANS}

Mixtures: contains two or more type of pure substance.

Example - heterogeneous, distillation, filtration.

{CAN BE SEPERATED BY PHYSICAL MEANS}

Electrolysis - water split —> hydrogen gas