organic chem

• What are hydrocarbons composed of?

  Hydrogen and carbon atoms only
• What is crude oil?

  Finite resource found in Earth's crust
• What is the origin of crude oil?

  Remains of organisms buried in mud
• What is crude oil a mixture of?

  A complex mixture of hydrocarbons
• How are carbon atoms arranged in hydrocarbon molecules?

  In chains and rings
• What are some fuels derived from crude oil?

  • Petrol
  • Diesel
  • Kerosene
  • Heavy fuel oil
  • Liquefied petroleum gases
• What is a feedstock in the petrochemical industry?

  • A raw material for industrial reactions
  • Used to produce petrochemicals
  • Example: Ethene for poly(ethene)
• What are some useful substances made from crude oil?

  Solvents, lubricants, detergents
• What do alkanes form?

  A homologous series
• What are the characteristics of homologous series like alkanes?

  • Same general formula
  • Differ by CH2 in molecular formulae
  • Gradual variation in physical properties
  • Similar chemical properties
• What is the general formula for alkanes?

  C$n$H$2n+$$2$
• What is the molecular formula of decane?

  C$10$H$22$
• How many carbon atoms are in hexane?

  Six carbon atoms
• What are covalent bonds in alkanes?

  Carbon atoms joined by C-C single bonds
• What is fractional distillation used for?

  • Separates crude oil into fractions
  • Based on different boiling points
  • Produces simpler, more useful mixtures
• How does fractional distillation work?

  Heated crude oil enters a fractionating column
• What happens to vapours during fractional distillation?

  Vapours rise and condense at different heights
• Why do small hydrocarbon molecules have low boiling points?

  They have weak intermolecular forces
• What characterizes the bitumen fraction of crude oil?

  Contains hydrocarbons with more than 35 carbon atoms
• What are the properties of crude oil fractions?

  • Mixtures of hydrocarbons
  • Similar numbers of hydrogen and carbon atoms
  • Similar boiling points
  • Similar ease of ignition
  • Similar viscosity
• What happens during complete combustion of hydrocarbons?

  Produces carbon dioxide and water
• What is the general equation for complete combustion?

  Hydrocarbon + oxygen → carbon dioxide + water
• What is the balanced equation for complete combustion of propane?

  C$3$H$8$ + 5O$2$ → 3CO$2$ + 4H$2$O
• What occurs during incomplete combustion?

  Produces carbon monoxide and carbon
• When does incomplete combustion occur in a Bunsen burner?

  When the air hole is closed
• What is cracking in hydrocarbons?

  • Reaction breaking larger hydrocarbons
  • Produces smaller, useful hydrocarbons
  • Some products are unsaturated
• What is the equation for cracking hexane?

  C$6$H$14$ → C$4$H$10$ + C$2$H$4$
• What are the two methods of cracking?

  Catalytic cracking and steam cracking
• What is catalytic cracking?

  Uses a temperature of approximately 550°C
• What is steam cracking?

  Uses a temperature over 800°C without a catalyst
• Why is cracking important?

  • Matches supply of fractions with demand
  • Produces alkenes as feedstock for petrochemical industry
• What is the difference between alkanes and alkenes?

  Alkanes are saturated; alkenes are unsaturated
• How do alkenes react differently from alkanes?

  Alkenes are more reactive than alkanes
• How can you test for a double C=C bond in a molecule?

  Alkenes react with bromine water
• What is the significance of ethene in the petrochemical industry?

  • Used as feedstock to make poly(ethene)
  • Important for producing polymers
• What series do alkenes form?

  Homologous series
• What is the general formula for alkenes?

  CnH2n
• How do alkenes differ from neighboring compounds?

  They differ by CH2 in molecular formulae
• What physical property varies gradually in alkenes?

  Boiling points
• What type of hydrocarbons are alkenes?

  Unsaturated hydrocarbons