Reactions of alkenes

• What are alkenes classified as?

  Unsaturated hydrocarbons
• What does the term "unsaturated" in alkenes indicate?

  They contain at least one carbon-carbon double bond
• What is the functional group of alkenes?

  Carbon-carbon double bond
• What do hydrocarbons consist of?

  Only hydrogen and carbon atoms
• Why can alkenes undergo addition reactions?

  The carbon-carbon double bond can open up
• What are the three types of addition reactions for alkenes?

  1. With hydrogen
  2. With water
  3. With halogens
• What is the alkene used in the hydrogen addition reaction example?

  Propene
• What happens when hydrogen gas is added to propene with a catalyst?

  The double bond breaks and propane forms
• What type of compound is propane?

  Alkane
• What alkene is used in the reaction with water?

  Ethene
• What conditions are required for the reaction of ethene with water?

  Catalyst and high temperatures
• What is produced when ethene reacts with water?

  Ethanol
• Why is ethanol significant in industry?

  It is used in alcoholic drinks and processes
• How is ethene separated from ethanol and water after the reaction?

  By cooling the mixture
• What method is used to separate ethanol from water?

  Fractional distillation
• How does fractional distillation work in this context?

  Ethanol evaporates first due to lower boiling point
• What is the common halogen used in the reaction with alkenes?

  Bromine
• What happens when bromine is added to ethene?

  It forms dibromoethane and decolorizes
• How can alkenes be distinguished from alkanes using bromine water?

  Alkenes decolorize bromine water, alkanes do not
• What color does bromine water have before reacting with alkenes?

  Orange
• What is the outcome of adding bromine water to an alkane?

  The solution remains orange
• What are the key points about alkenes and their reactions?

  • Alkenes are unsaturated hydrocarbons with double bonds.
  • They undergo addition reactions with hydrogen, water, and halogens.
  • Products include alkanes and alcohols.
  • Distinguishing alkenes from alkanes can be done using bromine water.