UNIT 5 - CRUDE OIL AND PLASTICS Flashcards
WHAT IS CRUDE OIL ?
The source of the vast majority of fossil fuels
It consists of a mixture of different chain length hydrocarbons
It is formed from the remains of marine organisms over millions of years
They were buried under mud and sand, high pressure, heat and lack of oxygen formed crude oil
WHY IS CRUDE OIL SPLIT INTO FRACTIONS ?
Crude oil is only useful when the hydrocarbons are separated
HOW DOES FRACTIONAL DISTILLATION WORK ?
Crude oil is heated until it vaporises
Gaseous oil enters the bottom of the column where the temperature is highest
Hydrocarbons with a boiling point higher than the temperature at that level condense and are piped away
Hydrocarbons with a lower boiling point remain gaseous and travel up to the next fraction which is cooler
The process repeats until the gas with the lowest boiling point is condensed at the top
WHAT HAPPENS TO THE PROPERTIES OF HYDROCARBONS AS THE CHAINS GET LONGER ?
Boiling point increases
Viscosity increases
Colour becomes darker
Cleanliness of burn decreases
(more soot given off in lower fractions)
Ease of ignition decreases
WHY DO LONG CHAIN HYDROCARBONS HAVE A HIGHER BOILING POINT ?
Intermolecular forces hold the hydrocarbons together
As the chain gets longer the intermolecular forces become stronger
More heat energy is therefore required to break them
WHAT IS BITUMEN USED FOR ?
Tar
WHAT IS DIESEL USED FOR ?
Lorry and train fuel
WHAT IS KEROSENE USED FOR ?
Aircraft fuel
WHAT IS NAPTHA USED FOR ?
Chemicals / plastics
WHAT IS PETROLEUM USED FOR ?
Car fuel
WHAT IS REFINERY GAS USED FOR ?
Portable burners
HOW DOES CRUDE OIL INFLUENCE THE ECONOMY ?
Countries that produce oil have a monopoly and set the price
Crude oil is so essential that countries would have to pay any price
Any crisis in an oil producing country impact the global economy
Burning fuels release CO2 - Links to global warming
Oil leaks when being transported negatively impact oceans
Oil rigs provide jobs
WHAT IS A COMBUSTION REACTION ?
A combustion reaction occurs when a chemical reacts with oxygen to produce heat, light and new products
COMPLETE COMBUSTION OF HYDROCARBONS REACTION ?
ISSUES ?
CH4 + 2 02 —–> CO2 + 2 H2O
CO2 - Cause of climate change and accelerated global warming
INCOMPLETE COMBUSTION OF HYDROCARBONS ?
ISSUES ?
2 CH4 + 3 O2 ——> 2 CO + 4 H2O
CO - Carbon monoxide - Poisonous
CH 4 + O2 ——-> C + 2 H2O
C - Soot - Breathing problems
BURNING HYDROGEN EQUATION ?
ADVANTAGES / DISADVANTAGES ?
2 H2 + O2 ——> 2 H2O
Just water produced
No adverse environmental affects
Renewable source - Made from electrolysis of water
DIS -
Large amounts of electricity required - Electricity made using fossil fuels
Heavy storage containers required
It is flammable and potentially explosive with air
WHAT IS THE FIRE TRIANGLE ?
The three components needed to maintain a fire
If any are removed the fire is extinguished
FUEL / HEAT / OXYGEN
HOW IS HEAT REMOVED FROM A FIRE ?
Water
REMOVING OXYGEN ?
Foam extinguishers - Fire blankets
REMOVING FUEL ?
More used for fire prevention
Fire breaks - Sections free of trees to stop fires spreading
Using non-flammable / fire resistant in everyday items
HOW DO YOU MEASURE ENERGY RELEASED FROM A FUEL ?
Place fuel in a spirit burner and measure the weight of the spirit burner and fuel
Measure 100cm3 of water into a conical flask
Measure the temperature of water ensuring the thermometer does not touch the bottom of the flask
Heat for 5 minutes
Measure the temp and calculate temperature rise
Weigh the burner again to calculate the temperature rise
Weigh the burner again to find the difference in weight
CALCULATE WITH THE FOLLOWING -
Mass of alcohol burned
WHAT ARE ALKANES -
Crude oil is mainly alkanes
They are single bonded hydrocarbons
They are saturated - Max. number of atoms around each carbon
NAME FIVE ALKANES :
METHANE - 1C
ETHANE - 2C
PROPANE - 3C
BUTANE - 4C
PENTANE - 5C
WHAT IS THE FORMULA FOR AN ALKANE ?
C (n) H (2n + 2)
WHAT IS CRACKING AND WHY DO WE DO IT ?
The most useful fractions of crude oil have short chains but long chains are the most common hydrocarbons
Cracking is the process of forming short chains from long chains
CRACKING EQUATION ?
Heated in the presence
of a catalyst and absence
of oxygen
Long Chain ——– > short chain + alkene
hydrocarbons hydrocarbons
WHAT ARE ALKENES ?
Alkenes are hydrocarbons that contain a carbon-carbon double bond
They are unsaturated hydrocarbons
Used in the production of plastics
NAME 3 ALKENES
Ethene - 2C
Propene - 3C
Butene - 4c
WHAT IS AN ISOMER ?
Molecules with the same molecular formula but different structure
WHAT ARE ADDITION REACTIONS ?
Double bonds make alkenes more reacitve than alkanes
Addition reactions add another molecule to a c=c bond, leaving a single bond in its place
ADDITION OF Br2 ?
Addition of Br2 is a good test for alkenes
the orange bromine turns colourless when it reacts with the alkene
ADDITION OF H2
Requires a nickel catalyst
Known as hydrogeneration
Used in the production of margarine
WHAT IS A MONOMER ?
A small reactive molecule that when joined together with other identical monomers forms a polymer
WHAT IS A POLYMER ?
Long chain molecules
Alkenes are used to make polymers in a process called polymerisation
WHAT IS POLYMERISATION ?
Polymerisation is when one of the bonds in a double bond breaks and then joins onto another monomer.
This process repeats until a long chain forms
NAME THE POLYMERS OF DIFFERENT MONOMERS
Ethene - Polyethene
Propene - Polypropene
Vinyl chloride - Polyvinyl chloride (PVC)
Tetrafluo-ethene - PTFE
WHAT IS POLYETHENE USED IN ?
Plastic bags and bottles
WHAT IS POLYPROPENE USED IN ?
Ropes and plastic crates
WHAT IS PVC USED IN ?
Used in drainpipes and window frames
WHAT IS PTFE USED IN ?
Non-stick coatings
WHAT ARE PROBLEMS LINKED TO PLASTIC DISPOSAL ?
Landfill ineffective as it fills up and does not decompose
Burning plastic release CO2 which contributes to global warming. Toxic gases also released
HOW TO REDUCE PLASTIC ISSUE ?
Recycling reduces the amount of waste going to landfill
Biodegradable plastics, not as durable
Recycling plastic requires less energy than making new plastic
Recycling conserves crude oil, less new plastic needed
