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Solutions

Solutions. CHARACTERISTICS OF A SOLUTION SOLUTION TERMINOLOGY FACTORS THAT DETERMINE SOLUBILITY FORMATION OF A SOLUTION. THE CHARACTERISTICS OF A SOLUTION. A solution is a homogeneous mixture. (Is our lip balm homogeneous or heterogeneous?)

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Solutions

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  1. Solutions CHARACTERISTICS OF A SOLUTION SOLUTION TERMINOLOGY FACTORS THAT DETERMINE SOLUBILITY FORMATION OF A SOLUTION

  2. THE CHARACTERISTICS OF A SOLUTION • A solution is a homogeneous mixture. (Is our lip balm homogeneous or heterogeneous?) • A solution may exist in any of the three states: gas liquid or solid. • Particle size distinguishes solutions from other mixtures, generally these particles are less than 5 x 10-7 cm in diameter.

  3. SOLUTION TERMINOLOGY • Solution  a homogeneous mixture of two or more substances of molecular or ionic particle size, the concentration of which may be varied, usually within certain limits. • Solute  the substance dissolved in the solvent, sometimes not clearly distinguishable from the solvent, but usually the lesser of the two. • Solvent  the medium in which the solute is dissolved. • Solubility  a measure of how much solute will dissolve in a given amount of solvent at a given temperature. • Saturated – concentration is a at a solubility limit for a given temperature • Unsaturated – concentration is less than the solubility limit • Supersaturated – manipulated (usually by T and P) solution where concentration is greater than the normal solubility limit • Miscible  two or more liquids dissolving in one another in all proportions • Immiscible  liquids that are insoluble in one another

  4. FACTORS THAT DETERMINE SOLUBILITY • The extent to which a particular solute dissolves in a given solvents depends on three things • The strength of the intermolecular forces (we will look at this concept in some detail) • The partial pressure of a solute gas over a liquid solvent (we will not go into this concept here) • The temperature (we will heat our mixture which increase the dissolving process)

  5. INTERMOLECULARFORCES • Solubility is a macroscopic process that depends on microscopic intermolecular (IM) forces • Generally speaking, if IM forces between solute-solute are similar to IM forces between solvent-solvent, then solute and solvent will probably dissolve in one another. In other words… “LIKE DISSOLVES LIKE”

  6. TYPES OF INTERMOLECULAR FORCES • London dispersion Forces: attraction of instantaneous and induced dipoles; exist between all molecules. • London dispersion forces increase with increasing molecular weight.

  7. TYPES OF INTERMOLECULAR FORCES • Dipole-Dipole: Dipole-dipole attractions take place when two or more neutral, polar molecules are oriented such that their positive (+) and negative (-) ends are close to each other.

  8. TYPES OF INTERMOLECULAR FORCES • Hydrogen Bonding: The hydrogen bond is really a special case of dipole forces. A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. The electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. The hydrogen then has the partial positive charge.

  9. WHAT TYPES OF INTERMOLECULAR FORCES ARE INVOLVED IN THE LIP BALM MIXTURE? • Lets look at the structures of the molecules involved • Some of our ingredients are solutions in their own right • For example – castor oil

  10. WHAT TYPES OF INTERMOLECULAR FORCES ARE INVOLVED IN THE LIP BALM MIXTURE? • Beeswax- a complex mixture

  11. WHAT TYPES OF INTERMOLECULAR FORCES ARE INVOLVED IN THE LIP BALM MIXTURE? • Carnauba wax- a complex mixture of mostly saturated fatty acid ester, and fatty acid ester diols • Vitamin E Oil

  12. WHAT TYPES OF INTERMOLECULAR FORCES ARE INVOLVED IN THE LIP BALM MIXTURE? • Lanolin- a complex mixture of cholesterol, fatty acid esters and even some wood alcohol (methanol) in crude mixtures. • Grapefruit oil- most likely the aroma is due to a mixture of terpenes: • Apple oil- mixture of esters such as ethyl isovalerate and a long chain pentanoate

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