7.2 Reactions of Alkenes and alcohols

• What is the general formula for alkenes?

  C_nH_2n
• Why are alkenes considered unsaturated?

  Because they contain at least one carbon-carbon double bond
• Name the first four alkenes.

  Ethene, propene, butene, and pentene
• What is the functional group of alkenes?

  • Alkenes have the functional group C=C
  • Functional groups are responsible for the reactions of organic compounds
• How do alkenes react with oxygen during combustion?

  They burn in air, often producing smoky flames due to incomplete combustion
• What is produced during the incomplete combustion of alkenes?

  Carbon or carbon monoxide (CO)
• What happens to the double bond in alkenes when they react with hydrogen, water, or halogens?

  The double bond is broken to form a single carbon-carbon bond
• What is the reaction of ethene with bromine (Br₂)?

  Ethene reacts with bromine to form a dibrominated alkane

  
• What is the functional group present in alcohols?

  –OH
• Name the first four alcohols.

  Methanol, ethanol, propanol, and butanol
• What are the reactions of alcohols when burned in air?

  • They produce carbon dioxide and water
  • They dissolve in water to form a neutral solution (pH of 7)
  • They react with sodium to produce hydrogen and a salt
  • They react with oxidizing agents to form carboxylic acids
• What is a common use of methanol?

  As a chemical feedstock and in anti-freeze
• What is ethanol commonly used for?

  As the main alcohol in alcoholic drinks and as a solvent
• How is ethanol produced?

  By fermentation of sugar with yeast using renewable sources
• What are the conditions for producing ethanol through fermentation?

  About 35°C, anaerobic conditions, and yeast enzyme catalyst
• What is the functional group of carboxylic acids?

  –COOH
• Name the first four carboxylic acids.

  Methanoic acid, ethanoic acid, propanoic acid, and butanoic acid
• What are the reactions of carboxylic acids?

  • They dissolve in water to produce acidic solutions (pH less than 7)
  • They react with metal carbonates to produce carbon dioxide, a salt, and water
  • They react with alcohols to produce esters in the presence of an acid catalyst
  • They do not ionize completely in solutions, making them weak acids
• Why are carboxylic acids considered weak acids?

  Because they do not ionize completely in solutions
• How does the pH of carboxylic acids compare to strong acids of the same concentration?

  Carboxylic acids have a higher pH (less acidic) than strong acids