Physical Properties of Simple Hydrocarbons

• 1. LDF - weakest, momentary dipoles, increase size = increase LDF
  2. Dipole-Dipole - polar molecules only, between molecules
  3. Hydrogen bonding, when H is covalently attatched to O, N, or F - strong, between molecules, increase H bonds = increase IMF = increase boiling point
• Alkanes - non polar, LDF, not soluble or low solubility when very small
• Alkenes - non polar, LDF, not soluble
• Alkynes - non polar, LDF, not soluble
• benzene - non polar, LDF, not soluble
• Alkyk halides - usually polar, LDF, DD, low solubility
• alcohol - polar (hydroxyl group), LDF, DD, H-bond, soluble
• carbolxylic acid - polar (carboxyl), LDF, DD, H-bond, soluble
• Ester - somewhat polar, LDF, DD, soluble is 4C or less; polarity decreases as carbon chain increases in size
• the stronger the IMF's the better the attraction between molecules, more energy needed to break bonds, therefore higher melting and boiling point
• homologous series: a group of molecules that have the same general formula, but only differ from one another in the length of the carbon chain
• in molecules from a homologous series, the larger the molecules, the higher the melting/boiling point