Mixtures are classified as homogeneous or heterogeneous, and homogeneous mixtures are further categorized by the diameter of the dispersed particles: suspensions (>500 nm), colloids (2–500 nm), and solutions (<2 nm), with particle size determining whether the dispersed phase separates over time or remains permanently dispersed due to intermolecular forces overcoming buoyancy and settling tendencies. Within solution chemistry, a solute (the dissolved substance, present in lesser amount) is dispersed within a solvent (the dissolving medium, present in greater amount, often water for aqueous solutions), and solution concentration is quantified via mole fraction (moles of solute divided by total moles of solute plus solvent), molarity (moles of solute per liter of solution), and molality (moles of solute per kilogram of solvent). This is a foundational topic within general/physical chemistry concerning the classification of mixtures and the measurement of solution concentration, underlying later treatments of colligative properties, reaction stoichiometry in solution, and equilibrium/partial-pressure calculations.
Mixtures are classified as homogeneous or heterogeneous, and homogeneous mixtures are further categorized by the diameter of the dispersed particles: suspensions (>500 nm), colloids (2–500 nm), and s…