Chapter 13 ALKENES

• What is the general formula for alkenes?

  CnH2n
• How do sigma bonds form?


  By overlapping two s orbitals
• What is a pi bond?

  Parallel overlap of two p orbitals
• Why are pi bonds weaker than sigma bonds?

  Electron density is spread out above and below the plane
• How many electrons are shared in a double bond?

  Four electrons
• What is the significance of high electron density in double bonds?

  It makes them open to electrophile attack
• What are stereoisomers?

  Same structural formula, different spatial arrangement
• What is E/Z isomerism?

  Different arrangements of atoms around a double bond
• What does Z in Z-pent-2-ene indicate?

  Same groups on the same side
• What does E in E-pent-2-ene indicate?

  Same groups on opposite sides
• What is the Cahn-Ingold-Prelog (CIP) priority rule?

  Atoms are prioritized by atomic number
• What determines the major product in reactions with unsymmetrical alkenes?

  Stability of the carbocation intermediate
• How does the number of alkyl groups affect carbocation stability?

  More alkyl groups increase stability
• What are alkenes considered in polymer chemistry?

  Monomers that form addition polymers
• Why are most polymers not biodegradable?

  They do not decompose easily
• What is one method of disposing of non-recyclable plastics?

  Incineration to generate electricity
• What is a disadvantage of incinerating waste plastic?

  It releases toxic fumes
• What conditions do some biodegradable polymers need to decompose?

  Oxygen and moisture
• What happens to photodegradable polymers when exposed to sunlight?

  They degrade over time
• What are the key features of electrophilic addition reactions involving alkenes?

  • Alkenes attacked by electrophiles
  • Hydration produces alcohols with steam and acid
  • Reaction with hydrogen halides forms haloalkanes
  • Unsymmetrical alkenes yield two products
• What are the environmental impacts of plastic disposal methods?

  • Incineration releases toxic fumes
  • Landfills contribute to pollution
  • Recycling reduces crude oil dependency
  • Biodegradable plastics decompose under specific conditions