fuels and hydrocarbons Flashcards
hydrocarbon definition
a compound containing only hydrogen and carbon
order (bottom to top) and uses of fractions in a fractionating column
bitumen: used to surface roads and roofs
fuel oil: fuel for large ships and some power stations
diesel oil: fuel for cars and some trains
kerosene: aircraft fuel
petrol: car fuel
natural gases: domestic heating and cooking
petrol, kerosene and diesel definition
non-renewable fossil fuels obtained from crude oil
methane definition
non-renewable fossil fuel found in natural gas
describe a homologous series
- same general formula
- differ by CH2 in molecular formula from neighbouring compounds
- similar chemical properties
- gradual variation in physical properties
complete combustion of hydrocarbon fuels definition
a reaction in which carbon dioxide and water are produced and energy is given out
why do members of the same homologous series have similar reactions
their molecules contain the same functional group
why is cracking necessary
allows for the production of smaller, more useful products from larger, less valuable ones. smaller chain hydrocarbons are easier to use and more in demand
molecular formulae of alkanes 1-5
methane: CH4
ethane: C2H6
propane: C3H8
butane: C4H10
pentane: C5H12
saturated hydrocarbon meaning
a hydrocarbon that only contains single bonds between atoms
why are the alkanes saturated hydrocarbons
due to alkanes only containing single bonds
molecular and structural formulae of alkanes 1-3
ethene: C2H4
propene: C3H6
but-1-ene: C4H8
but-2-ene: C4H8
why is methene not possible
methene would only contain one carbon atom, but alkenes need to contain the functional group C = C, thus requiring a minimum of 2 carbon atoms
why are alkenes unsaturated hydrocarbons
they must contain the functional group C = C, therefore containing a double bond and unsaturated hydrocarbons are those with 1 or more double bonds
how to distinguish between alkanes and alkenes
using bromine water. mix bromine water and the hydrocarbon. will turn colourless if alkene but remain brown if alkane.
polymer definition
substance of high average relative molecular mass made up of small repeating units
how are the uses of polyethene related to its properties
flexible, strong, waterproof, chemically resistant - bottles, bags, food containers
how are the uses of polypropene related to its properties
lightweight, resistant, strong - ropes, carpet
how are the uses of polychloroethene related to its properties
electrical polyethene - pipes, windowsills, packaging
how are the uses of polytetrafluoroethene related to its properties
slippery, unreactive - coating for non-stick pans, containers
problems with polymers
- availability of starting materials
- persistence in landfill
- gases produced during combustion
- need to be sorted to be recycled
advantages of recycling polymers
reduces landfill, conserves starting/natural materials, reduce greenhouse gases
disadvantages of recycling polymers
time consuming to sort them, expensive
