alkenes

• What is the general formula for alkenes?

  C$n$H$2n$
• What does it mean for alkenes to be unsaturated hydrocarbons?

  It means they contain double bonds.
• What type of reactions do alkenes undergo?

  Alkenes undergo addition reactions.
• What is the structural formula for ethene?

  • Ethene: C$2$H$4$
  • Structural formula: CH$2$ = CH$2$
• What is the structural formula for buta-1,3-diene?

  • Buta-1,3-diene: C$4$H$6$
  • Structural formula: CH$2$ = CH - CH = CH$2$
• Why are double bonds in alkenes reactive?

  Because they have high electron density.
• What is the formula for cyclopentene?

  C$5$H$8$
• What type of molecules are electrophiles?

  Electrophiles are electron pair acceptors.
• What are examples of electrophiles?

  Examples include H$+$ and NO$2+$.
• What does the curly arrow represent in reaction mechanisms?

  The curly arrow shows the movement of electrons.
• How does bromine react with alkenes?

  Bromine adds to the alkene and causes a color change from brown-orange to colorless.
• What is formed when bromine water is added to an alkene?

  A colorless dibromoalkane is formed.
• What happens to the bromine molecule when it approaches an alkene?

  An induced dipole is created in the bromine molecule.
• What is a carbocation intermediate?

  A carbocation intermediate is a molecule formed during a reaction that has a positive charge on a carbon atom.
• What is the difference between primary, secondary, and tertiary carbocations?

  Primary has one alkyl group, secondary has two, and tertiary has three alkyl groups attached.
• Why are tertiary carbocations more stable than primary carbocations?

  Tertiary carbocations are more stable because they have more alkyl groups that can donate electrons to stabilize the positive charge.
• What is the role of sulfuric acid in the reaction with alkenes?

  Sulfuric acid acts as a catalyst in the reaction with alkenes.
• What is the mechanism for the reaction of alkenes with hydrogen halides?

  1. The double bond attacks the delta positive hydrogen.
  2. The bond between hydrogen and halogen breaks.
  3. A carbocation intermediate is formed.
  4. The halide ion attacks the carbocation.
  5. A haloalkane is produced.
• What is the mechanism for the reaction of alkenes with sulfuric acid?

  1. Sulfuric acid donates a proton to the alkene.
  2. A carbocation intermediate is formed.
  3. The alkyl hydrogen sulfate is produced.
  4. The intermediate can be converted to an alcohol.
• What molecule is added to alkenes to form alkyl hydrogen sulfate?

  Sulfuric acid
• What is the role of sulfuric acid in the reaction with alkenes?

  It acts as a catalyst to form alcohol from an alkene.
• What is the formula for sulfuric acid?

  H$_2SO_4$
• What is formed as an intermediate when alkenes react with sulfuric acid?

  Alkyl hydrogen sulfate
• How does the mechanism of sulfuric acid acting as a catalyst work in the reaction with alkenes?

  It interacts with the alkene to form a carbocation intermediate and alkyl hydrogen sulfate.
• What is hydrolysis in the context of alkyl hydrogen sulfate?


  It is the process of adding cold water to alkyl hydrogen sulfate to form alcohol.
• What product is formed when alkyl hydrogen sulfate undergoes hydrolysis?

  Ethanol
• What does the term "lysis" in hydrolysis mean?

  It means to break or cleave something.
• What is the overall reaction when alkenes react with sulfuric acid and water?

  Alkenes react with sulfuric acid to form alkyl hydrogen sulfate, which then reacts with water to form alcohol and regenerate sulfuric acid.
• What is the significance of using asymmetric alkenes in reactions with sulfuric acid?

  They can produce two different products due to the different possible arrangements of the alkyl groups.
• What are alkenes considered in the context of plastics?

  They are monomers used to make polymers.
• What is the process called when monomers join together to form polymers?

  Addition polymerization
• What are examples of natural and synthetic polymers?

  • Natural polymers: Proteins, natural rubber
  • Synthetic polymers: Polyethylene, polypropylene
• Who discovered vulcanized rubber?

  Charles Goodyear
• What is the purpose of adding plasticizers to polymers?

  To make the polymers more flexible.
• How do plasticizers affect the properties of PVC?

  They push the polymer chains apart, making the material more flexible.
• What are the properties of polyalkenes in terms of their intermolecular forces?

  They are mostly nonpolar and have van der Waals forces between chains.
• How does the length of a polyalkene chain affect its melting point?

  Longer chains have higher melting points due to closer packing and stronger van der Waals forces.
• What is the effect of branching in polyalkene chains on their properties?

  Shorter chains with more branching tend to be more flexible and weaker.
• What type of forces are present in PVC due to the presence of chlorine?

  Permanent dipole-dipole forces
• Why is PVC considered useful for outdoor applications?

  It is strong, durable, and can withstand various weather conditions.