Fuels and atmospheric science Flashcards
Where do they believe natural gas and crude oil to be from?
Formed from ancient remains of microscopic animals living in the sea. Then covered by layers of sediment and over millions of years they became natural gas and crude oil trapped in rocks
What is a finite resource?
A resource that limits our access to it as it is not made any more (or are being made very slowly)
What is crude oil made of?
A complex mixture of hydrocarbons
What are hydrocarbons?
Compounds that only contain hydrogen and carbon
How many covalent bonds can carbon atoms make?
4 bonds
What state is crude oil at at room temperature
Liquid
What is crude oil used for?
- fuels for vehicles, aircrafts, ships, heating and power stations
- feedstock or raw materials for the petrochemical industry
What are petrochemicals?
Substances made from crude oil such as polyethene
What is natural gas?
A mixture of hydrocarbons in the gas state
Give two fuels that can be obtained from crude oil and what they’re used for
- petrol - vehicles
- kerosene - aircrafts
What does non-renewable mean and give an example of a non-renewable source
It means a substance is being used up faster than they’re being made so one day they’ll run out - fossil fuels (e.g petrol)
How can crude oil be separated?
Fractional distillation
Where does the industrial fractional distillation take place?
In a large metal fractionating column
What is done to crude oil in the fractionating column
Heated strongly to evaporate it
Where is the column the hottest and coldest?
Hottest - bottom
Coldest - top
What happens to the vapours as they travel up the column?
They cool down and condense when the reach a part of the column that is cold enough (below their boiling points)
What happens to vapours with low boiling points
They don’t condense and leave the fractionating column as gases
What has the highest boiling point
Bitumen and it leaves the column as a hot liquid at the bottom
What is the order of substances produced in the column from top to bottom and give a use for all of them?
Gases - domestic heating and cooking
Petrol - fuel for cars
Kerosene - fuel for aircraft
Diesel oil - fuel for some cars and trains
Fuel oil - fuel for large ships and power stations
Bitumen - surfacing roads and roofs
Is each fraction pure hydrocarbons or a mixture?
Mixture of hydrocarbons
What is the trend in the number of atoms in molecules over the fractions?
Increases down the fractions
What is the trend for boiling point over the fractions?
Increases down the fractions
What is the trend of the ease of ignition over the fractions?
Easy at the top and difficult at the bottom
What is the trend for viscosity (how easy it is to flow) over the fractions?
Flows easily at the top and difficult at the bottom
What are alkanes?
Hydrocarbons that only have a single covalent bonds between the atoms in their molecules
What is a homologous series?
A sequence of compounds with the same functional group and similar chemical properties
What do the compounds in a homologous series have in common?
- molecular formulae of neighbouring compounds differ by CH2
- they have the same general formula
- they show gradual variation through physical properties (e.g melting point)
- they have similar chemical properties
Google what different hydrocarbons look like: including methane, ethane and propane
DID U DO IT???
U BETTER HAVE OR I WILL STEAL YOUR KNEECAPS
What are methane, ethane and propane?
The first three alkanes
How do methane, ethane and propane differ in their molecular formulas?
They each increase by one carbon atom and two hydrogen atoms
What is the general formula for the alkane homologous series?
C(n)H(2n+2)
meaning the number of hydrogen atoms is twice the amount of carbon plus 2
What is the trend between the number of carbon atoms and the boiling point?
As the number of carbon atoms increases, the boiling point gradually increases as well
Why can alkanes be separated through fractional distillation?
Because there is a difference in boiling points across them
What do alkanes produce when reacted with excess oxygen?
Carbon dioxide and water