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boiling point elevation When the normal boiling point of a solvent is raised by the presence of a solute. Can be found using the equation ΔTb = i · Kb · msolute, where i is the van ‘t Hoff factor, Kb is the molal boiling-point elevation constant (ebullioscopic constant) for the solvent, and msolute is the molality of the solute.

colligative property Properties of a solution that depend only on the amount of solute. Also see boiling point elevation, freezing point depression, vapor pressure, and osmotic pressure.

colloid A mixture in which one substance is evenly dispersed (but not dissolved) in another.

freezing point depressionWhen the normal freezing point of a solvent is lowered by the presence of a solute. Can be found using the equation ΔTf = i · Kf · msolute, where i is the van ‘t Hoff factor, Kf is the molal freezing-point depression constant (cryoscopic constant) for the solvent, and msolute is the molality of the solute.

molality Moles of solute over kilograms of solvent. Often denoted as m.

mole fraction Moles of substance A over moles of both substances A and B. Usually denoted by the letter X; is a unitless number.

osmotic pressure The amount of pressure necessary to stop osmosis. Can be found using the equation π = iMRT, where i is the van ‘t Hoff factor, M is the molarity, R is the gas constant (0.08206 L · atm · mol-1 · K-1), and T is the temperature in Kelvins.

Raoult’s law States that the vapor pressure of a solution is dependent on the mole fraction of its solvent. Psoln = Xsolvent · Psolvent, where Xsolvent is the mole fraction of the solvent and Psolvent is the vapor pressure of the pure solvent.

solute A substance dissolved by a solvent to form a solution.

solution Homogeneous mixture containing a solvent and one or more solutes.

solvent The dissolving agent in a solution. A common solvent is water.

Tyndall effect The scattering of light caused by colloidal particles.

van ‘t Hoff factor The number of ions a solute dissociates into. Often referred to as i.

vapor pressure The pressure of a gas at equilibrium over its liquid phase.

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