C9 Crude oil and fuels Flashcards
Alkane
Saturated hydrocarbon with the general formula CnH2n +2, for example methane, ethane and propane. Each carbon atom forms four single covalent bonds.
Alkene
Unsaturated hydrocarbon with a carbon-carbon double bond, its general formula is CnH2n
Cracking
The reaction used in the oil industry to break down large hydrocarbons into smaller, more useful ones
Distillation
Separation of a liquid from a mixture by evaporation followed by condensation
Double bond
A covalent bond made by the sharing of two pairs of electrons
Flammable
Easily ignited and capable of burning rapidly
Fraction
Hydrocarbons with similar boiling points separated from crude oil
Fractional distillation
A way to separate liquids from a mixture of liquids by boiling off the substances at different temperatures, then condensing and collecting the liquids
Hydrocarbon
A compound with only hydrogen and carbon
Mixture
When some elements/compounds are mixed together, but do not react together. Mixtures are not pure substances.
Oxidised
A substance that has oxygen added to it/it has lost electrons
Saturated hydrocarbon
A hydrocarbon with only single bonds between its carbon atoms, contains as many hydrogen atoms as possible in each molecule
Thermal decomposition
The breakdown of a compound by heating it
Unsaturated hydrocarbon
A hydrocarbon whose molecules contain at least one carbon - carbon double bond
Viscosity
A liquid’s thickness/resistance to flowing or pouring
Homologous series
A group of organic compounds that react in a similar way e.g. alkanes and alkenes
First four alkanes
Methane: CH4
Ethane: C2H6
Propane:C3H8
Butane: C4H10
How does the length of the carbon chain affect the properties of a hydrocarbon?
The shorter the carbon chain, the more runny and less viscous a hydrocarbon is.
The shorter the carbon chain, the more volatile hydrocarbons are(they have lower boiling points).
The shorter the carbon chain, the more flammable(easier to ignite) the hydrocarbon is.
Equation for the complete combustion of a hydrocarbon
Hydrocarbon + oxygen: carbon dioxide + water vapour + energy
Waste products in complete combustion of a hydrocarbon
Carbon dioxide and water
How was crude oil formed
Crude oil is a fossil fuel formed from the remains of plants/animals like plankton that died millions of years ago and were buried in mud. Over millions of years, with high temperature and pressure, the remains turned to crude oil, which are drilled up from the rocks it’s found
Finite resources
Non-renewable Resources that will run out as they aren’t formed quickly enough to be considered replaceable, fossil fuels like coal, oil and gas
Crude oil
A mixture of lots of different hydrocarbons, most of which are alkanes
Stages of fractional distillation
1) Oil is heated until it turns into gas. The gases enter a fractionating column(and the liquid bit is drained off).
2) In the column there’s a negativemtemperature gradient(it’s hotter at the bottom and gets cooler as you go up).
3) The longer hydrocarbons have high boiling points. They condense into liquids and drain out of the column early on, when they’re near the bottom. The shorter hydrocarbons have lower boiling points, so condense and drain out later on, near the top of the column where it’s cooler.
4) You end up with the crude oil mixture being separated into different fractions, each fraction has a mixture of hydrocarbons with a similar number of carbon atoms, so have similar boiling points. These fractions have different boiling points so condense at different places in the tower