CHM 2046C Key Terms Chapter 11-McMurry

Solutions and Their Behavior

Aerosol: colloid in which either a liquid or solid is dispersed in a gas

Colligative property: a property of a solvent that is different in the presence of a solute but that varies only according to the number of solute particles present per molecule of solvent, not on the identity of the solute

Colloid (colloidal dispersion): an intermediate state between a solution and a suspension. The dispensed phase is dispersed throughout the dispersing medium, but the particles are larger than in a solution. Unlike a suspension, the particles do not settle out

Emulsifying agent: a material that allows two otherwise insoluble liquids to form an emulsion (a colloid formed when the dispersing medium and the dispersed state are both liquids)

Emulsion: a colloid formed when the dispersing medium and the dispersed state are both liquids

Enthalpy of hydration: for an ionic compound, this is the enthalpy change that corresponds to taking the separated ions in the gas phase and transforming them to the hydrated ions in solution

Entropy: a measure of the disorder of a system; the more disordered a system is, the higher the entropy

Foam: a colloid in which a gas dispersed in either a liquid or solid

Gel: a colloid in which a liquid is dispersed in a solid

Henry’s Law: water-loving; materials that are strongly attracted to water are said to by hydrophilic

S_g = k_HP_g

Hydrophilic: water-loving; materials that are strongly attracted to water are said to by hydrophilic

Hydrophobic: water-fearing; materials that are not strongly attracted to water or that are insoluble in water are said to be hydrophobic

Hypertonic solution: a solution of higher solute concentration than a cell

Hypotonic solution: a solution of lower solute concentration than a cell

Ideal solution: a solution that obeys Raoult’s law; solutions approach ideality as the solute concentration is decreased and as the strength of the solute-solvent interactions more closely approximate those of the solvent-solvent interactions

Immiscible: a term used to describe two liquids that are not soluble in each other to an appreciable extent

Isotonic solution: a solution containing an equal solute concentration as a cell

Le Chatelier’s Principle: a change in any of the factors determining equilibrium will cause the system to adjust so as to reduce or minimize the effect of the change

Miscible: a term used to describe two liquids that are soluble in each other to an appreciable extent

Molality: moles of solute per kilogram of solvent

Mole fraction: the number of moles of one component of a mixture divided by the total number of moles of all components in the mixture. The sum of all of the mole fractions in a mixture is 1

Osmosis: the movement of solvent molecules through a semipermeable membrane from a region of lower solute concentration into a region of higher solute concentration

Osmotic pressure: during the process of osmosis, the pressure exerted by the solution of higher concentration when equilibrium has been established between solvent flowing into the solution due to osmosis and flowing out of the solution due to the pressure of the solution

Parts per million: the number of grams of solute per million grams of solution; it may be calculated by taking the mass of solute, dividing by the mass of the solution, and then multiplying by 1,000,000. It also corresponds to mg of solute per kilogram of solution, which (for a dilute solution) is also approximately equal to the mg of solute per liter of solution

Raoult’s law: the vapor pressure exerted by the vapor of the solvent in solution is equal to the mole fraction of the solvent in the solution multiplied by the vapor pressure of the pure solvent

Reverse osmosis: a process in which a pressure sufficient to overcome the osmotic pressure is applied to the solution of higher solute concentration such that solvent will flow in the opposite direction as would occur in the process of osmosis

Saturated solution: a solution in which the concentration of the solute equals its solubility

Semipermeable membrane: a membrane that allows some species to pass through but not others

Sol.: a colloid in which a solid is dispersed in another solid

Solid sol: a colloid in which a solid is dispersed in another solid

Solubility: the concentration of solute in a solution in which there is an equilibrium between dissolved solute and undissolved solute

Solute: in a solution, the component present in the smaller amount; it can be considered to be the dissolved material in the solution

Solution: a homogeneous mixture of tow or more substances in a single phase

Solvent: in a solution, the component present in the largest amount; it can be considered to be the medium in which the other component in the solution is dissolved

Standard heat of solution: the enthalpy change that occurs when sufficient solute is dissolved to form a solution with a 1 molal concentration

Supersaturated solution: an unstable solution that temporarily contains a concentration of solute greater than the solute’ solubility

Surfactant: a substance that affects the properties of surfaces

Suspension: in a suspension, the particles of a material are temporarily dispersed in a solvent as large aggregates but these particles settle out

Tyndall effect: the scattering of light that occurs when a beam of light is passed through a colloid

Unsaturated solution: a solution in which the concentration of the solute is less than its solubility

Van’t Hoff factor: the ration of the experimentally measure freezing point depression of a solution to the value calculated assuming that the solute is a molecular solute

Weight percent: the number of grams of solute per hundred grams of solution; it may be calculated by taking the mass of solute, dividing by the mass of the solution and then multiply by 100