C7

• isomers

  Isomers are molecules that have the same molecular formula, but different structural formulas, this means they are made of the same atoms, but the atoms are arranged differently.

  the two molecules above both have the formula C5H12- meaning 5 carbon atoms and 12 hydrogen atoms. However the atoms are arranged differently, which is why they have different names.

  
• Alkanes are a homologous series of molecules that contain:

  1. Only carbon and hydrogen atoms.
  2. Only single bonds (alkanes have no double bonds).
• A homologous series is a group of organic compounds that have similar chemical properties, due to them having the same functional group.
• whats that

  ethane

  
• what's that

  butane

  
• a hydrocarbon with a single bond can be referred to as saturated
• Hydrocarbons are compounds that contain carbon and hydrogen only
• Simplest hydrocarbons

  • Methane
  • Ethane
  • Propane
  • Butane
• General formula for alkanes

  If the compound contains n carbon atoms, it will contain 2n + 2 hydrogen atoms
• Octane's molecular formula is C8H18
• Alkanes


  • They are saturated compounds with every carbon atom having four single covalent bonds
• Changing a single bond to a double bond in an alkane


  Results in an alkene
• Alkanes are a homologous series of hydrocarbons that contain only carbons and hydrogen atoms with no double bonds
• Properties of alkanes


  • Boiling point increases with chain length
  • Shorter alkanes are gases at room temperature, longer alkanes are liquids, and very long chains can be solid
  • Shorter alkanes are more volatile and evaporate easily
  • Longer alkanes are more viscous
  • Shorter alkanes are more flammable
• Shorter alkanes are more flammable and easier to ignite or burn
• Complete combustion of hydrocarbons like alkanes with oxygen forms carbon dioxide and water, releasing energy
• Complete combustion is an exothermic reaction
• Hydrogen and carbon in the hydrocarbon are oxidized during combustion
• Combustion reactions

  Hydrocarbons react with oxygen to form carbon dioxide and water, releasing energy
• The properties of hydrocarbons like alkanes depend on the length of their carbon chain
• Shortest hydrocarbons have the lowest boiling points, making them the most volatile and flammable, which makes them great fuels
• Complete combustion only occurs if there is enough oxygen available
• Complete combustion produces carbon dioxide and water, releasing energy
• 1. Crude oil is formed from the remains of dead plants and animals, particularly plankton.
  2. These organic remains were covered by mud and sand, and buried in the earth.
  3. Over millions of years, these organic remains were compressed under a lot of heat and pressure.
  4. The heat and pressure chemically changed the organic remains into crude oil.
• Crude oil

  A mixture of hydrocarbons with different boiling points
• Refining crude oil

  1. Heating crude oil to a very high temperature

  2. Hot gaseous hydrocarbons rise up the fractionating column

  3. Hot gaseous hydrocarbons cool down

  4. Hydrocarbons condense

  5. Liquid hydrocarbons collect in trays and drain out
• Fractionating column


  • Hot gas rises
  • Hydrocarbons condense when they become cooler than their boiling point
  • Longer chain hydrocarbons condense at the bottom of the fractionating column
  • Shorter chain hydrocarbons condense at the top of the fractionating column
• fractional distillation

  
• Petrol: B

  Liquified Petroleum Gas: A

  Bitumen: C

  
• A feedstock is a raw material used to provide reactants for an industrial reaction.
• A petrochemical is a substance made from crude oil, via chemical reactions.
• different hydrocarbons in crude oil are all feedstocks, but the useful things we then make from those hydrocarbons (polymers, solvents, lubricants, detergents etc.), are all petrochemicals. 
• Shorter chain alkanes have lower melting and boiling points, so are more flammable, and more volatile.
• Cracking is the process in which larger chain hydrocarbons are split into smaller, more useful hydrocarbons
• cracking is a thermal decomposition reaction
• catalytic cracking


  1. First, some long chain alkanes are heated until they vaporise into a gas
  2. Then they're passed over a hot, powdered aluminium oxide catalyst 
  3. This breaks the long chain alkanes into a shorter chain alkane and an alkene
• steam cracking

  Steam cracking is different because there is no catalyst involved. Instead the vaporised long chain alkane is mixed with steam at very high temperatures.
• Alkenes are hydrocarbons with a double bond between two carbon atoms
• cracking

  When a long chain alkane is cracked, there aren't enough hydrogen atoms to make two alkanes. Hence, cracking will always produce one alkane and one alkene.

  
• intro to alkenes

  1. Alkenes are similar to alkanes. Alkenes are also hydrocarbons and also an example of a homologous series.
  2. The difference is that alkenes have a double bond between two carbon atoms, whereas alkanes only have single bonds.
  3. Another way to express the presence of the double bond between two carbon atoms is to say that alkenes are 'unsaturated'.