Crude oil and fuels Flashcards
What is a hydrocarbon?
Are compounds made of ONLY hydrogen and carbon
How is crude oil formed?
By the remains of ancient biomass that lived and died millions of years ago
What are the alkanes?
hydrocarbons that only have single bonds
What are the first 4 alkanes?
Methane,ethane, propane,butane
What is the general formula for the alkanes?
Cn H2n+2
How does the boiling point of a hydrocarbon depend on chain length?
As chain length increases, the boiling point increases
How does the viscosity of a hydrocrabon depend on the chain length?
The longer the chain, the higher viscosity
How does the flammability of a hydrocrabon depend on chain length?
Shorter the chain length, the higher the flammability
How can the different alkanes in crude oil be separated?
Fractional distillation
What is a fraction?
a group with similar chain length hydrocarbons
Name five useful fuels produced from fractional distillation?
Petrol, diesel, kersosene,Gases
Name four useful materials produced from crude oil fractions?
gasoline, diesel, kerosene, and bitumen
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 products of cracking?
Shorter chain hydrocarbons and an alkene
What are alkenes?
Unsaturated hydrocarbon with a double bond between the carbon atoms.
What are alkenes used for?
to make chemicals such as plastic, polymer, and for fuels
Describe the reactivity of alkenes compared to alkanes?
Alkenes are much more reactivity alkanes
How can you test for alkenes?
Bromine water, if it turns colourless it contains alkenes
What are properties of thermosoftening polymers?
-melt when heated, can be remoulded (recycled)
-Only weak intermolecular forces between the polymer chains.
What are properties of thermosetting polymers?
-Do not melt when heated.
-Strong bonds cross-link (strong covalent bonds) between the polymer chains
What are properties of low densisty poly(ethene)?
-Flexible and stretchy
-Made using very high pressures with only a trace of oxygen present.
-Branched polymer chains can’t pack together - fewer atoms in the same volume (low density)
What are properties of high densisty poly(ethene)?
-Rigid and strong
-Made using catalyst at 50°C and -only slightly raised pressure.
-Straight polymer chains can pack together - more atoms in same volume (high density)
