organic chemistry

• What is fractional distillation?


  when crude oil is separated into substances with similar boiling points/fractions
• Alkenes general formula


  CnH2n
• Alkanes


  a hydrocarbon containing only single covalent bonds
• what is crude oil?

  Crude oil is a finite resource that is found in the Earth’s crust. It is the remains of organisms that lived and died millions of years ago - mainly plankton which was buried in mud. Crude oil is a complex mixture of hydrocarbons. The carbon atoms in these molecules are joined together in chains and rings. In the ball and stick models below, carbon atoms are black and hydrogen atoms are white.
• why can fractional distillation be used?

  Fractional distillation is used to separate crude oil into simpler, more useful mixtures. This method can be used because different hydrocarbons have different boiling points.
• Key fact: One way to remember the names of the fractions in order is: Lazy Penguins Keep Drinking Hot Beer.

  
• General formula

  The general formula for the alkanes is CnH2n+2, where n is the number of carbon atoms in the molecule.
• General formula

  The general formula for the alkanes is CnH2n+2, where n is the number of carbon atoms in the molecule.
• in alkenes if its C4, how many Hs would there be

  2x4=8+2=10 hydrogens
• how do you draw c4 h10 (butane)

  alkene diagram for butane

  
• different alkenes table

  
• describe the properties of alkenes

  Alkenes are weakly polar just like alkanes but are slightly more reactive than alkanes due to the presence of double bonds. The π electrons which make up the double bonds can easily be removed or added as they are weakly held.
• alkenes vs alkanes

  alkanes and alkenes are hydrocarbons, meaning they are made up of hydrogen and carbon only. However, alkanes are saturated hydrocarbons consisting of single bonds only whereas alkenes are unsaturated hydrocarbons which include a carbon-carbon double bond.
• alkanes are saturated hydrocarbons, but what does saturated mean?

   saturated hydrocarbons are hydrocarbons in which all of the carbon atoms are bonded to four other atoms. 
• what is a polymer?


  A polymer is a very long molecule. Polymers are made up of many repeating units called monomers.
• A daisy chain is a good model for a polymer. Each individual daisy represents a monomer. As they join together to make a long chain, they make a model of a polymer.

  
• Polymers can be natural or synthetic
• Synthetic polymers often have these properties in common:

  • they are chemically unreactive
  • they are solids at room temperature
  • they can be moulded into shape
  • they are electrical insulators
  • they are strong and hard-wearing
• is polystyrene a synthetic or natural polymer?


  polystyrene is a synthetic polymer as it isn't natural and is man made.
• natural polymers....


  Examples of naturally occurring polymers are silk, wool, DNA, cellulose and proteins. 
• synthetic polymers...


  nylon, polyethylene, polyester, Teflon, and epoxy
• what are the disadvantages of polymers...

  Unfortunately, the lack of reactivity of polymers make them difficult to dispose of. When they are thrown away, they do not break down very quickly and so stay in the environment for a long time. Plastic pollution poses a big environmental challenge.
• why is plastic a polymer?


  because plastic is a substance made of many repeating units.
• Synthetic polymers tend to have names including the word ‘poly’. For example, polyethene or polystyrene. Some are better known by their common names like nylon or elastane.

  
• Which of the following is not a polymer?

  Protein

  Glucose

  Cellulose

  DNA


  Glucose, as it is a simple sugar, a single molecule.
• Petrol obtained from crude oil contains sulfur impurities.

  Explain why sulfur impurities are removed before petrol is burned in car engines.

  SO2 in the atmosphere causes smog, and reacts with rain to form sulphuric acid — acid rain. 
• Name the process which produces smaller hydrocarbon molecules from heavy fuel oil.


  cracking
• what is cracking?


  the process of breaking down large hydrocarbon molecules into smaller ones by heating them in the presence of a catalyst.
• what are the conditions of cracking


  Thermal cracking uses harsh conditions like high temperature and high pressure.
• what are the types of cracking?

  Thermal cracking, steam cracking, hydro cracking, and fluid catalysed cracking 
• whats a real life example of cracking?


  Cracking is the most important process for the commercial production of gasoline and diesel fuel
• is fractional distillation harmful to the environment?

  Fractional distillation alone is not harmful to the environment. In fact, fractional distillation converts crude oil, otherwise unusable, into more valuable products.
• What are polymers made up of?

  Polymers are made up of smaller units called monomers.
• Why are polymers considered a diverse group of substances?

  Because they make up all sorts of different materials.
• What is the formula for the monomer propene?

  The formula for propene is $C_3H_6$.
• How can you identify a polymer molecule?

  You can identify a polymer molecule by noticing a repeating unit within it.
• How would you represent a polymer made from 400 propene monomers?

  You would draw the repeating unit and put $400$ in the corner.
• What does the letter 'n' represent in polymer chemistry?

  The letter 'n' represents the number of repeating units in the polymer.
• What type of bonds are found within polymers?

  Polymers contain covalent bonds.
• What needs to be broken to melt or boil polymers?

  The intermolecular forces between separate polymer molecules need to be broken.