org chem midterms

• Qualitative analysis


  • The analysis of the species present in a given compound
  • It also helps know the composition of the compound
• The detection of various elements present in an organic compound
• Elements commonly present in organic compounds


  • Carbon
  • Hydrogen
  • Oxygen
  • Nitrogen
  • Halogens
  • Sulphur
  • Phosphorus
• Organic compounds

  • Always have a carbon atom
  • Combustible/flammable/inflammable
  • Covalently bonded
  • Low melting and boiling points (>360°)
  • Mostly insoluble in H2O (nonpolar)
  • When dissolve in water, separates into molecules
  • Soluble in org solvents (diethyl ether, toluene, and dichloromethane)
  • Non-electrolytes
  • Slow reaction
  • Less stable/unstable
  • Complex structure
  • Isomerism

  
• Inorganic compounds

  • Non-flammable
  • Ionic bonds/electrovalent
  • Soluble in H2O (polar)
  • When dissolve in water, separates into ions
  • Electrolytes
  • Faster reaction
  • High melting and boiling points
  • Simpler structure
  • More stable
  • Rarely exhibit isomerism

  
• Solubility test


  "Like dissolves like", similar polarities are soluble in one another (polar-polar, org-org)
• Naphthalene (nonpolar) is insoluble in water due to its nonpolar nature
• Urea (polar) is soluble in water due to its ability to form hydrogen bonds
• Sodium nitrate (polar) is soluble in water due to the polar water molecules surrounding and separating the Na+ and NO3- ions
• Naphthalene (nonpolar) is soluble in petroleum ether (nonpolar) due to similarity in polarity
• Urea (polar) and sodium nitrate (polar) are insoluble in petroleum ether (nonpolar) due to lack of polarity
• Boiling point


  • The temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid
  • Liquid to gas state
  • The boiling point at one atmospheric pressure is known as the normal boiling point
• Solubility test


  "Like dissolves like", similar polarities are soluble in one another (polar-polar, org-org)
• Factors affecting boiling point


  • Pressure
  • Adding impurities
  • Structure
  • Polarity
  • Strength of intermolecular forces
  • Length of carbon-carbon chain
  • Branching decreases the boiling point
• Naphthalene (nonpolar) is insoluble in water due to its nonpolar nature
• Urea (polar) is soluble in water due to its ability to form hydrogen bonds
• Melting point


  • The temperature at which a solid material transitions to a liquid phase at atmospheric pressure
  • This temperature reflects the point where the kinetic energy of the molecules overcomes the ordered structure of the solid phase
  • This is the point at which both liquid and solid phase exists at equilibrium

  
• Factors affecting melting point


  • Molecular symmetry (conformation, orientation, odd vs even chain length)
  • Molecular size (length of carbon-carbon chain)
  • Polarity/intermolecular forces
  • Impurities
• Naphthalene (nonpolar) is soluble in petroleum ether (nonpolar) due to similarity in polarity
• Factors affecting both melting and boiling points


  • Molecular weight
  • Intermolecular forces (hydrogen bonding, dipole-dipole interactions, van der Waals forces)
  • Structural shape

  
• Melting and boiling points of specific organic compounds


  • n-Butyl Alcohol (1-Butanol)
  • tert-Butyl Alcohol (t-Butanol)
  • n-Amyl Alcohol (1-Pentanol)
  • Salicylic Acid
  • Stearic Acid
  • Benzoic Acid

  
• Beilstein test (halogen)


  1. Create a loop on a copper wire

  2. Heat in a flame until it stops changing color

  3. Cool, dip in chloroform, and reheat
• Boiling point


  • The temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid
  • Liquid to gas state
  • The boiling point at one atmospheric pressure is known as the normal boiling point
• Factors affecting boiling point


  • Pressure
  • Adding impurities
  • Structure
  • Polarity
  • Strength of intermolecular forces
  • Length of carbon-carbon chain
  • Branching decreases the boiling point
• Melting point


  • The temperature at which a solid material transitions to a liquid phase at atmospheric pressure
  • This temperature reflects the point where the kinetic energy of the molecules overcomes the ordered structure of the solid phase
  • This is the point at which both liquid and solid phase exists at equilibrium
• Factors affecting melting point


  • Molecular symmetry (conformation, orientation, odd vs even chain length)
  • Molecular size (length of carbon-carbon chain)
  • Polarity/intermolecular forces
  • Impurities
• A green flame indicates the presence of halogens
• Factors affecting both melting and boiling points


  • Molecular weight
  • Intermolecular forces (hydrogen bonding, dipole-dipole interactions, van der Waals forces)
  • Structural shape
• Silver nitrate test (halogen)


  1. Add nitric acid to monochloroacetic acid, boil gently

  2. Introduce silver nitrate solution
• A white precipitate confirms the presence of chloride ions
• Ferrox test (oxygen)


  1. Place organic solutions in test tubes

  2. Add ferrox reagent, stir
• Color change indicates the presence of oxygen (red)
• Lead acetate test (sulfur)


  1. Mix albumin with NaOH and lead acetate

  2. Boil the solution
• Melting and boiling points of specific organic compounds


  • n-Butyl Alcohol (1-Butanol)
  • tert-Butyl Alcohol (t-Butanol)
  • n-Amyl Alcohol (1-Pentanol)
  • Salicylic Acid
  • Stearic Acid
  • Benzoic Acid
• A black precipitate signals the presence of sulfur
• Beilstein test (halogen)


  1. Create a loop on a copper wire

  2. Heat in a flame until it stops changing color

  3. Cool, dip in chloroform, and reheat
• A green flame indicates the presence of halogens
• Silver nitrate test (halogen)


  1. Add nitric acid to monochloroacetic acid, boil gently

  2. Introduce silver nitrate solution
• A white precipitate confirms the presence of chloride ions
• Ferrox test (oxygen)


  1. Place organic solutions in test tubes

  2. Add ferrox reagent, stir