C14 - Organic Chemistry Flashcards
Organic compound
Organic compounds are those which contain carbon
Hydrocarbons
A hydrocarbon is a compound that contains only hydrogen and carbon atoms
Ways to represent hydrocarbons (3)
- Displayed Formulae
- General Formulae
- Structural Formulae
Structural isomers
Structural isomers are compounds that have the same molecular formula but different structural formulae
Homologous series
This is a series or family of organic compounds that have similar features and chemical properties due to them having the same functional group
Functional group
The functional group is a group of atoms which are bonded in a specific arrangement that is responsible for the characteristic reactions of each member of a homologous series
Saturated compounds
Have molecules in which all carbon-carbon bonds are single bonds (e.g. alkanes)
Unsaturated compounds
Unsaturated compounds consist of molecules in which one or more carbon-carbon bonds are not single bonds (they contain double bonds of carbon)
Fuel
A fuel is a substance which when burned, releases heat energy
* This heat can be transferred into electricity, which we use in our daily lives
Common foosil fuels
Coal, natural gas and hydrocarbons
Main constituent of natural gas
Methane (CH4)
Petroleum
Petroleum is also called crude oil and is a complex mixture of hydrocarbons which also contains natural gas
* It is a thick, sticky, black liquid that is found under porous rock (under the ground and under the sea)
Fraction
A group of molecules with a defined boiling point range which distils off at the same place during fractional distillation
Process of fractional distillation (3 steps)
- Crude oil enters the fractionating column and is heated so vapours rise
- Vapours of hydrocarbons with very high boiling points will immediately turn into liquid and are tapped off at the bottom of the column
- Vapours of hydrocarbons with low boiling points will rise up the column and condense at the top to be tapped off
Fractional distillation
Properties of fractions
- Viscosity: more carbon atoms results in increased attraction between molecules so it is more viscous
- Colour: as carbon chain increases, colour gets darker
- Melting/boiling point: larger molecule results in greater intermolecular force meaning an increased boiling point
- Volatility: (the tendency for a substance to vaporise) the greater molecular size, the less volatile
Uses of fractions
- Refinery gas: heating and cooking
- Gasoline: fuel for cars (petrol)
- Naphtha: raw product for producing chemicals
- Kerosene: for making jet fuel (paraffin)
- Diesel: fuel for diesel engines (gas oil)
- Fuel oil: fuel for ships and for home heating
- Lubricating oil: for lubricants, polishes, waxes
- Bitumen: for surfacing roads
Alkanes
Alkanes are a group of saturated hydrocarbons
* general formula: C(n)H(2n+2)