TYPES OF SOLUTIONS

• Solutions

        – are mixtures of two or more substances evenly distributed throughout a single phase.  Atoms, ions, or molecules are thoroughly  mixed in a solution such that each part of the mixture has a uniform composition and properties.
• •SOLUTE

  • substance dissolved in a solution and is usually present in smaller amount.
• •SOLVENT

  • Dissolving medium.
• Unsaturated Solution- Contains less solute than the solvent’s capacity to dissolve.
• Saturated Solution- Contains the maximum amount of solute that the solvent can dissolve at a certain temperature.
• Supersaturated Solution- Contains more dissolved solute than is present in a saturated solution.
• “Expanding the Solvent”-Overcoming the intermolecular forces in the solvent to give room for the solute.
• “Expanding the Solute” -Separating the solute into its individual components.
• Concentation of the Solution

  • is a measure of the amount of solute in a given amount of solvent or solution.
•   The mole fraction (x) of a component in a solution is equal to the number of moles of that component divided by the total number of moles of all the components present. The sum of the mole fractions of all components in a solution will always be equal to one.
• MOLALITY (m)

      - the number of moles of solute per kilogram of the solvent.
• MOLARITY (M)

      - refers to the number of moles of solute per liter of solution.

      - it is especially useful in doing stoichiometric calculations involving solutions.
• Parts Per Million (ppm)

      - Expresses the number of parts of solute per one million parts of the solution.
• SOLUTION STOICHIOMETRY-   Stoichiometric analysis of solutions involves the use of a balanced chemical equation and can be done through these general steps: 

  1.Express the given amount of substance in moles.2.Convert the moles of the given substance to the moles of the desired substance using a stoichiometric factor derived from the balanced chemical equation.3.Convert the moles of the sought substance to any other desired units in expression.
• Solubility

        - the maximum amount of a solute that can dissolve in a given amount of solvent at a specific temperature.
• . Nature of Solute and Solvent

  ØConcept of “like dissolves like”-Similarity in the polarity of substances.-Ionic and non-polar substances are soluble in polar solvents.Nonpolar solutes are soluble in nonpolar solvents
• ØParticle Size

  -Smaller particle size of  a solid solid means there are greater surface areas exposed to the solvent; thus the solute has a higher solubility.
• ØStirring

  • Helps to slightly increase the solubility of a solid solute since this disperses the solvent particles around the solute, allowing the fresh portions of the solvent of the solvent to come in contact with the solid.
• Temperature

      The increase in temperature raises the kinetic energy of the solution, allowing the solvent particles held together by intermolecular forces of attraction.
• Temperature

      The increase in temperature raises the kinetic energy of the solution, allowing the solvent particles held together by intermolecular forces of attraction.

      There are some substances, however, for which the solubility remains constant with changes in temperature.
• Pressure

    Pressure has an appreciable effect on the solubility of gases in gas-liquid solutions, but it has no effect on the solubility of solid salts in water.
• Henry’s Law

  -The solubility of a gas in a liquid is directly proportional to the partial pressure if the gas above the liquid.-Named after it’s proponent, the British chemist William Henry (1775-1836).
• Colligative Properties

  -The collective term for quantity-dependent properties of solution.-Some properties of solutions depend on the nature of their constituent substances, while others depend solely on the number of the solute particles in the solution.
• qElectrolytes

          - particles that ionize in a solution; as a result,

            they conduct electricity
• qNonelectrolytes

          - particles that do not ionize at all in a solution

            and thus do not conduct electricity.
• Raoult’s Law- -The relationship between the vapor pressure of the solution and the vapor pressure of the solvent depends on the concentration of the solute in the solution.-States that the vapor pressure of a solvent over a solution (P_solvent) is equal to the product of the vapor pressure of the pure solvent (P_solvent^0) and the mole fraction of the solvent in the solution (x_solvent).