Organic Chemistry 1
- Created by: Amy_sprott
- Created on: 18-12-17 09:02
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- Organic Chemistry
- Alkanes
- Properties
- Burn and react with halogens
- Very unreactive
- Saturated hydrocarbons
- General formula CnH2n+2
- Boiling points
- Longer carbon chain = higher boiling point
- Stronger VDW forces due to more electrons in the molecule
- Alkanes that are isomers
- More branched carbon chain = lower boiling point
- Weaker VDW due to molecules not being able to pack together tightly
- More branched carbon chain = lower boiling point
- Longer carbon chain = higher boiling point
- Properties
- Petroleum
- Formation
- Slow decay of marine animals, under heat and pressure in the absence of air
- Properties
- Mainly alkanes
- No use in its raw form
- Must be partly separated
- The separation of crude oil into its fractions
- Due to the compounds in crude oil having different boiling points
- Longer chainboiling point = higher boiling point due to greater VDW's
- Due to the compounds in crude oil having different boiling points
- The separation of crude oil into its fractions
- Must be partly separated
- Formation
- Fractional distillation
- The separation of crude oil into its fractions
- Due to the compounds in crude oil having different boiling points
- Longer chainboiling point = higher boiling point due to greater VDW's
- Due to the compounds in crude oil having different boiling points
- Method
- 1. Crude oil is vaporised
- 2. Vapour is passed into a fractionating column that's hotter at the bottom
- 3. As the vapour rises it cools
- 4. Molecules condense at different points die to different boiling points
- Fraction properties
- As C chain gets longer...
- Hydrocarbons become more viscous
- Hydrocarbons are harder to ignite
- Hydrocarbons are less volatile
- Hydrocarbons have higher boiling points
- As C chain gets longer...
- The separation of crude oil into its fractions
- Cracking
- What is it?
- The thermal decomposi-tion of alkanes
- Splitting long hydrocarbons into shorter chains
- Because shorter chains are in more demand
- Splitting long hydrocarbons into shorter chains
- Breaking of C-C bonds
- The thermal decomposi-tion of alkanes
- Conditions
- Thermal cracking
- 900°c, 70 atm, no catalyst
- Produces alkenes
- 900°c, 70 atm, no catalyst
- Catalytic cracking
- 450°c, 1-2 atm, zeolites as catalyst
- Produces motor fuels (aromatics, cyclic alkanes, branched alkanes)
- 450°c, 1-2 atm, zeolites as catalyst
- Thermal cracking
- What is it?
- Reforming
- When straight hydrocarbons are converted into branched chain alkanes and cyclic alkanes
- Both products burn more efficiently
- When straight hydrocarbons are converted into branched chain alkanes and cyclic alkanes
- Combustion
- Alkanes readily burn in the presence of oxygen
- Complete combustion
- Produces carbon dioxide and water
- Incomplete combustion
- Produces carbon monoxide and/or carbon particulates
- Formation of Sulphur oxide
- Sulphur impurities found in some fractions and produce SO2 when burned
- Removal of SO2
- Gasses passed through a scrubber containing Calcuim oxide or Calcuim carbonate
- Reaction forms gypsum (Calcium Sulphate IV)
- Used to make plasterboard
- Reaction forms gypsum (Calcium Sulphate IV)
- Gasses passed through a scrubber containing Calcuim oxide or Calcuim carbonate
- Alkanes
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