solubility

• solubility: extent to which a compound (the solute) dissolves in a liquid (solvent)

  • intermolecular forces/interactions in the solute needs to be overcome for dissolution
  • "Like dissolve like"
• "Like dissolve Like"

  • polar solutes in polar solvents
  • nonpolar solutes in nonpolar solvents
  • cause: similar intermolecular forces expected between similar types of molecules
• Water as solvent

  • is very polar (O-H)
  • high H-bonding capacity (as both donor and acceptor)
  • only very polar or ionic molecules dissolve in water
• organic compounds as solvents

  • each compound varies is polarity
  • usually a lot of C-C and C-H bonds are nonpolar
  • most are nonpolar or moderately polar
• organic compound solvents

  • very nonpolar: hexane, cyclohexane, benzene carbon tetrachloride
  • moderately polar: diethyl ether, tetrahydrofuran, acetone, tetra-butanol
  • very polar: CH3OH/CH3C2OH, much higher ratio of polar atoms/bonds to nonpolar ones
• hydrophobic: nonpolar parts of a molecule that are not attracted to water
• hydrophilic: able to dissolve in water
• Vitamins (2 main types)

  • fat-soluble: hydrophobic, nonpolar, insoluble in water
  • water-soluble: very polar, hydrophilic
• soap and detergents

  • molecules made up of a polar "head group" and a nonpolar "tail"
  • slightly soluble in water but at a higher concentration
  • forms micelles at parts it does not dissolve
  • dirt and grease are made up of nonpolar greasy molecule
• biomolecules

  • organic compounds found in biological systems: are small, with molecular weights of less than 1000g/mol
  • 4 main families: simple sugars, amino acids, lipids, and nucleotides
  • function: synthesize larger compounds that have important cellular functions