Fuels and Earth Science Flashcards
what are hydrocarbons?
compounds which contain carbon and hydrogen only
what is crude oil?
- complex mixture of hydrocarbons
- containing molecules in which carbon atoms are in chains or rings
- important source of useful substance i.e. fuels and feedstock
- finate resource
- NEED TO KNOW
how can crude oil be separated?
- fractional distillation
- heated until mostly gas (liquid bitumen drained off)
- entre fractional column
- longer hydrocarbons have higher boiling points, so turn back to liquids, drain off
- shorter hydrocarbons drain off later
- separating all the substances
what are the 6 fractions of crude oil?
- gas
- petrol
- kerosene
- diesel oil
- fuel oil
- bitumin
what are the uses of gas?
heating, cooking
what are the uses of petrol?
fuel for cars
what are the uses of kerosene?
fuel for aircraft
what are the uses of diesel?
fuel for cars and trains
what are the uses of fuel oil?
fuel for large ships, and power stations
what are the uses of bitumen?
surface roads
what are the properties of gases and petrol from crude oil?
- 3 carbons(gases)
- 8 carbons(petrol)
- easy to ignite
- low viscosity(runny)
- low boiling point
what are the properties of fuel oil and bitumen from crude oil?
- 40 carbons(fuel oil)
- 70+ carbons(bitumin)
- hard to ignite
- high boiling points
- high viscosity(treacle)
what homologous series are most of the fractions part of?
alkana homologous series
what is the equation for the molecular formula of the the compounds in the homologous series?
CH2
i.e. Ch4
and C2H6
what are the first 2 elements In the homologues series?
methane then ethane
how do the boiling points go down the homologous series?
they go up down the group
all the homologous series have…
similar chemical properties
what is the equation for complete combustion?
hydrocarbon + oxygen = carbondioxide + water
-energy given out
when do you get incomplete combustion?
when theres no enough oxygen so produces carbon and carbon monoxide
how does carbon monoxide behave as a toxic gas?
- combine with red blood cells and stop blood from carrying oxygen
- stops blooding going to brain, death, coma
what are the problems with incomplete combustion forming carbon?
- falls forms soot
- makes buildings look dirty, reduces air quality, worse respiratory problems
what are the problems with sulphur dioxide?
- mixes with clouds and form dilute sulfuric acid, acid rain
- lakes become acidic, animals die
- kills trees, damages limestone
when fuels are burnt in engines how are pollutants formed?
- oxygen and nitrogen recact at high temperatures to produce oxides of nitrogen
- smog, air pollution
advantages of using hydrogen rather then petrol in cars?
- clean fuel
- only water as waste product
- renewable resource
disadvantages of using hydrogen rather then petrol in cars?
- special, expensive engine
- expensive to manufacture hydrogen gas
- hard to store hydrogen
what are the non renewable energy sources in crude oil and natural gas?
crude oil- petrol, kerosene, diesel oil
natural gas- fossil fuels
what is cracking?
turns long saturated alkane molecules into smaller unsaturated alkene and alkane molecules which are more useful
why are molecules needed to be cracked into smaller ones?
-more demand for products like petrol and diesel than for bitumen
