Organic Chemistry Flashcards
What is organic chemistry all based on
Carbon
What can carbon compounds can be grouped into
Homologous series
Compounds in the homologous series have:
- same general formula
- similar chemical reactions
- trend in physical properties
- same functional group
Alkane
C-C
- ane
Allene
C = C
- ene
Alcohol
- OH
-ol
Amine
NH2
-amine
Carboxylic acid
COOH
- oic acid
Aldehyde
CHO
-al
Ketone
-C=O
-one
Esters
-COO
-yl -oate
Halogenoalkane
C-X (x could be F, I, Cl)
fluoro -
Chloro -
Bromo -
Iodo -
Nitrile
- C=N (triple)
-nitrite
What is an isomerism
Molecules can have the same molecular formula but different arrangements in space (I.e. different structural formulae)
What are Positional isomers
The position of the functional group is changed
What are functional group isomers
Change the functional group
Which functional groups are group isomers
Aldehyde - Ketones
Alkene - Cycloalkanes
What are alkanes
Are the homologous series with the general formual CnH2n+2
They are saturated hydrocarbons
Alkanes boiling point
Relatively low due to weak van dear walls forces between molecules (C-H bonds aren’t considered as polar so there are no dipole- dipole/ hydrogen bonds). The larger the Mr the more van dear wasp, therefore the boiling point increases
Chains effect on boiling points
The more branches you have the lower the boiling point is. Due to less/weaker van dear wall forces between molecules
What are alkanes generally used for
Typically used as fuels. This involves combustion reactions with oxygen
Complete combustion word equation and formula
Hydrocarbon + oxygen -> carbon dioxide + water
CnH2n+2 + 3n+1/2 O2 -> nCO2 + (n+1) H2O
What happens if there is insufficient oxygen present
Incomplete combustion. This can from
CO -> Carbon monoxide , toxic colourless gas
C -> carbon , black solid
Environment
Carbon dioxide effect
A particulate that results in global warming
Environment
Carbon effect
A particulate it can results in breathing issues and global dimming
Environment
Nitrogen oxides effect
E.g. NO, NO2, N2O4 etc
Theses are formed when N2 in the air reacts with O2 in the air and in the engine at very high temperature
Environment
Sulfur dioxide effect
Causes acid rain
SO2 + H2O + 1/2O2 -> H2SO4
This affects rivers, trees and buildings
Process of fractional distillation
1) heat petroleum to a gas, around 400 degrees
2) put the gas in a fractionating column
3) vapours of hydrocarbons with very high obinlgi points will condes into a liquid lower down the column
4) vapours of hydrocarbons with lower boiling points will condense higher at the top of the column
5)the separated fractions are removed
Why is cracking used
It takes longer, less useful alkanes and breaks them into shorter more useful hydrocarbons.
It will always produce a mixture of alkanes and alkenes
Why is cracking used
It takes longer, less useful alkanes and breaks them into shorter more useful hydrocarbons
Thermal cracking
Uses very high temperatures and high pressure
It produces a lot of small alkanes and alkenes
Catalytic cracking
High temperature and a catalyst, zeolite crystal
This can form a lot of aromatic compounds such as Benzene
What is the test for alkenes?
Add bromine water, Br2
The could changes form orange to colourless
What is the free radical solution
Alkanes can be made into halogenalkanes through this process
What are the three steps within free radical substitution
1 - initiation
2 - propagation
3 - termination
What is ozone
Ozone, O3 forms a layer in our atom sop here. The ozone layer was becoming depleted due to CFC ( chlorofluorocarbon)
What happened when CFC were being emitted into the atmosphere
They can catalyse for the decomposition of ozone into oxygen
What alternatives do we use instead of CFC
Nowadays we use hydrofluorcarbons as they do not generate Cl. radicals.
They are used in cool and refrigerants and propellents.
Why is the ozone being depleted
CFCs absorb UV radiation, breaking down the carbon halogen bond to form free radicals that can catalyse ozone depletion
what is a catalytic converter
are equipped to modern cars to reduce harmful emissions
small amounts of Pd\Pt\Ir on a honeycomb support, high surface area so little metal required
what does a catalyst do?
lowers the activation energy of a reaction by providing an alternate pathway
