fuels and earth science Flashcards
what is crude oil
it is our main source of hydrocarbons
how are different hydrocarbons separated in crude oil
fractional distillation
what is petrol used for
fuel for cars
what is kerosene used for
fuel for aircraft
what is diesel used for
fuel for some cars and larger vehicles
what is fuel oil used for
fuel for ships
what is bitumen used for
used to make roads
what are some properties of short hydrocarbons
-easy to ignite
-lower relative melting and boiling point
what are some properties of long hydrocarbons
-hard to ignite
-higher relative melting and boiling points
what is complete combustion
are reaction that only forms carbon dioxide and water
when does incomplete combustion happen
when there is a limited supply of oxygen
what products does incomplete reaction form
carbon monoxide and carbon in a form of soot
and water
why is carbon monoxide toxic
it can combine with red blood cells and stop them from carrying oxygen
why is sulfur dioxide a pollutant
they can mix with clouds to form sulfuric acid. this will then form as acid rain
why are nitrogen oxides pollutants
they can contribute to acid rain and at ground level, it can cause photochemical smog
what are some pros of using hydrogen as fuel
no pollutants released
what are some cons of using hydrogen as fuel
you need a special expensive engine to use and it is also hard to store
what is cracking
it is the splitting up of long chain hydrocarbons
what is the optimum temperature for cracking
400celsius-700
what is the optimum pressure for cracking
70atm
what is the catalyst used in cracking
aluminium oxide
how does cracking help supply and demand
shorter hydrocarbons are in higher demand and there is an excess of long chain hydrocarbons. the cracking of long chain hydrocarbons means that there is more shorter hydrocarbons available
how was our atmosphere formed
- 4.5 billion years ago, the early atmosphere consisted of CO2 and water vapour formed by volcanoes. no O2.
-4 billion years ago, the earth cooled and water vapour turned into the oceans. CO2 disolved into water.
-2.4 billion years ago, rocks containing iron oxide starts to form. oxidation suggests an increase of O2. fossils also prove this
-there are microorganisms called cyanobacteria which use photosynthesis to produce O2
-a different type of iron oxide forms which needs lots of O2(Fe2O3)
-oxygen increases until plants evolve
explain how the greenhouse effect occurs
-sun gives out radiation
-some of the radiation is absorbed by the earth
-some of it is re-emmited back into space
-greenhouse gasses trap some radiation from leaving, warming up the planet
-the more gases, the warmer the planet
