Victoria Hon Andrea Ma Period 5

Solution– a homogenous mixture of two or more substances in a single phase Soluble- capable of being dissolved Solvent- dissolving medium in a solution Solute- substance being dissolved

Solutions occur when two or more substances form a mixture that has the same composition and properties throughout. Examples: Water, sterling silver, brass Suspensions contain particles so large that they settle out unless the mixture is constantly stirred/agitated. Examples: Sand in water, pulp in orange juice, mud in water

Colloids contain particles that are intermediate in size, between those in solutions and suspensions.  The particles in a colloid are small enough to be suspended in the solvent by the constant movement of the surrounding molecules.

Though many colloids appear homogeneous because the individual particles cannot be seen, the particles are large enough to scatter light. When light is shone through a colloid, the particles are scattered, making the beam visible. In this way, a beam of light distinguishes a colloid from a solution.

SolutionsColloidsSuspensions HomogeneousHeterogeneous Particle size: nm; can be atoms, ions, molecules Particle size: nm; can be aggregates or large molecules Particle size: over 1000 nm; cam be aggregates or large particles Do not separate on standing Particles settle out Cannot be separated by filtration Can be separated by filtration Do not scatter lightScatter light (Tyndall effect) May scatter light, not transparent

An electrolyte is a substance that dissolves in water to give a solution that conducts electricity. Examples: NaCl, HCl A non-electrolyte is a substance that does not conduct an electric current when dissolved in water. Examples: sucrose

 Increasing the surface area of the solute: because the dissolution process occurs at the surface of the solute, it can be speeded up if the surface area is increased. (example: crushing sugar cubes increases the surface area, so it dissolves quickly)  Agitating the solution: stirring helps to disperse solute particles, bringing fresh solvent into contact with the solute surface (example: stirring sugar into iced tea)  Heating the solvent: as the temperature of the solvent increases, more collisions between the solvent molecules and the solute occur, helping to separate solute molecules from one another and to spread them throughout the solvent molecules, making dissolving faster. (example: sugar dissolves more quickly in warm water than in cold water)

When a solution contains the maximum amount of dissolved solute, it is called a saturated solution. A solution that contains less solute than a saturated solution under the same conditions is called an unsaturated solution. A supersaturated solution contains more dissolved solute than a saturated solution under the same conditions.

Immiscible- liquid solutes and solvents that are not soluble in each other Miscible- liquids that dissolve freely in one another in any proportion Solution equilibrium- physical state in which the opposing processes of dissolution and crystallization of a solute occur at equal rates Effects of pressure on solubility: increases in pressure increase gas solubilities in liquid Effects of temperature on solubility: as the temperature increases, the average kinetic energy of the molecules also increases, decreasing solubility Effervescence- the rapid escape of a gas from a liquid in which it is dissolved Henry’s LawHenry’s Law: The solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid.

Molarity- the number of moles of solute in one liter of solution Molarity (M) = amount of solute (mol) volume of solution (L) Molality- the concentration of a solution expressed in moles of solute per kilogram of Solvent Molality (m) = moles of solute (mol) mass of solvent (kg)