Fuels and hydrocarbons

• What is organic chemistry?

  The chemistry of carbon compounds
• Why can carbon form a vast number of compounds?

  It can form strong covalent bonds with itself
• What does the ability of carbon to form long chains enable?

  An almost infinite variety of carbon compounds
• How many covalent bonds does carbon always form?

  Four covalent bonds
• What is a functional group?

  A specific atom or group of atoms
• How are organic molecules classified?

  By the dominant functional group
• What is a homologous series?

  Organic compounds with the same functional group
• What happens every time a carbon atom is added to the chain?

  Two hydrogen atoms are also added
• What are the types of formulae used to represent organic compounds?

  • General Formulae
  • Displayed Formulae
  • Molecular Formulae
  • Structural Formulae
• What does a general formula indicate?

  The composition of any member of a series
• What is the general formula for alkanes?

  C$nH_{2n+2}$
• What does the general formula for alkanes tell you?

  Hydrogen atoms based on carbon count
• What do displayed formulae show?

  The spatial arrangement of all atoms and bonds
• What do molecular formulae represent?

  The actual number of each atom in a molecule
• What is the purpose of structural formulae?

  • Clarifies the structure of a molecule
  • Omits most actual covalent bonds
  • Shows important bonds like double/triple bonds
  • Identical groups can be bracketed
• What are the characteristics of a homologous series?

  Same functional group, general formula, similar properties
• How does each member of a homologous series differ?

  By -CH$_2$ - group
• What happens to physical properties as a homologous series is ascended?

  They gradually change, like boiling point
• What is crude oil?

  A complex mixture of hydrocarbon compounds
• Why is crude oil considered a finite resource?

  It is used up faster than formed
• How did crude oil form?

  From high pressures and temperatures on biomass
• What are hydrocarbons?

  Compounds containing hydrogen and carbon only
• Where is crude oil typically found?

  In porous rock under the ground and sea
• What is the state of crude oil at room temperature?

  Thick, sticky, black liquid
• What is fractional distillation?

  A process to separate mixtures into fractions
• Why is crude oil not very useful as a substance?

  Because it is a mixture of hydrocarbons
• What are fractions in the context of crude oil?

  Groups of hydrocarbons with similar chain lengths
• What is the significance of the different fractions of crude oil?

  Each fraction has many different applications
• How are fractions in petroleum separated?

  Through a process called fractional distillation
• What do the molecules in each fraction have in common?

  They have similar properties and boiling points
• What determines the boiling points of the hydrocarbons in a fraction?

  The number of carbon atoms in the chain
• How is the size of each hydrocarbon molecule related to its composition?

  It is related to the number of carbon and hydrogen atoms
• What type of compounds do most fractions contain?

  Mainly alkanes
• What are alkanes?

  Compounds of carbon and hydrogen with single bonds
• What is crude oil primarily composed of?

  A mixture of hydrocarbons
• Why do different hydrocarbons in crude oil have different boiling points?

  Longer chains have higher boiling points
• What happens to crude oil in a fractionating column?

  It is heated and separated into fractions
• How does the temperature gradient in a fractionating column affect the separation process?

  It allows different fractions to condense at various temperatures
• How does the continuous operation of the fractionating column work?

  Heated crude oil is piped in and fractions are drawn off
• What are the main fractions obtained from crude oil during fractional distillation?

  • Gases
  • Petrol
  • Kerosene
  • Diesel oil
  • Fuel oil
  • Bitumen