chem in bio

• covalent bonds:

  • shares electrons either equally (nonpolar) or unequally (polar)
• electronegativity: the ability of an atom to attract the pair of electrons in a covalent bond

  • same elements = nonpolar covalent (neither one stronger)
  • different elements = polar covalent (one stronger than other)
• ionic bonds:

  • donation of electrons (cation/donor and anion/recipient)
  • results in charged ions = allows bond (opposites attract)
• compounds with ionic bonds: ionic compounds/salts

  • does not consist of molecules but charged atoms
• INTRAmolecular forces: within atoms of a molecule

  • covalent bonds
  • ionic bonds

  INTERmolecular forces: in between atoms of separate molecules

  • perm dipole
  • ion-dipole
  • vdw
  • h bond
• bonds from strongest to weakest:

  1. covalent
  2. ionic
  3. ion dipole
  4. h bond
  5. vdw
• adding heat --> bonds break

  removing heat --> bonds form
• soap is antipathic

  • hydrophilic and hydrophobic
  • interacts with both oil and water
• water property: cohesion benefits

  • capillary action
  • high surface tension
• water property: 1. high specific heat / 2. Hvap benefits

  1. moderates environment temperatures
  2. evaporative cooling
• water property: physical phenomenons

  • expansion upon freezing and denser in liquid form than solid form
  • results from stable hbonds in solid form rather than other forms
• water property: universal solvent

  • ionic + water: easy bond break (ion dipole)
  • polar + water: soluble material via hbond dissociation
  • nonpolar + water: insoluble material (hydrophobic interaction)