Organic Chemistry Flashcards
Each fraction of crude oil contains a mixture of different … … Of a similar size and with similar properties
Hydrocarbon molecules
Before crude oil can be used, it must first be … Into fractions. This process is called …
Separated
Fractional distillation
Each fraction of crude oil contains a mixture of different … Meaning that the boiling point of the fraction is not a fixed temperature but a …
Compounds
Range
Volatility and flammability in crude oil fractions
- low boiling point evaporate easier
- easier fraction evaporates more volatile it is
- more volatile easier mixes with air
- fraction ignites and burns easily
- smaller molecules in a fraction more volatile and flammable the fraction
- lower boiling points more volatile and flammable
Viscosity in crude oil fractions
- thick and sticky = highly viscous
- high viscosity not easily poured
- longer hydrocarbon chains more viscous fraction will be
- higher boiling point more viscous
Appearance of crude oil fractions
- longer chain of molecules darker colour of fraction
- the colour of a fraction depends on size of the molecules it contains
- higher boiling point darker colour of fraction
Smokiness of crude oil fractions
-higher boiling point more smokey and dense smoke
Refinery gas uses
Bottled gas and chemicals for cooking and heating
Gasoline uses
Petrol fuel for cars
Kerosene/paraffin uses
Jet fuel, stoves, central heating, lamps
Diesel oil uses
Lorries, buses, cars, some boats
Fuel oil uses
Ship fuel, large industrial boilers, oil fired power stations, ships
Bitumen/residue uses
Roads, roofing (waterproof)
Explain how a fractioning column works
- all the crude oil is heated
- vaporises and it is passes into bottom of a fractioning tower
- fractioning tower hot at the bottom and cold at the top
- hydrocarbons rise up the tower and condense at different points due to differing boiling point
Complete combustion
In a plentiful supply of oxygen all hydrocarbons burn to form carbon dioxide and water vapour and give out heat
Give and example of a complete combustion
Methane (CH4) the main constituent of natural gas which burns to give carbon dioxide and water
CH4 + 2O2 –> CO2 + 2H2O
Incomplete combustion
In a limited supply of oxygen, all hydrocarbons burn to form carbon monoxide or carbon and water vapour and give out heat. Less heat is given out so it is less efficient. As well as being poisonous, carbon monoxide is colourless, tasteless and odourless which makes it difficult to detect
Give an example of incomplete combustion
Methane (CH4) burns to give carbon monoxide plus water
2CH4 + 3O2 –> 2CO + 4H2O
Catalytic converters are used in cars to remove … like carbon monoxide and nitrogen oxides from the … cars eg 2CO + 2NO –> N2 + 2CO2
Pollutants
Exhaust
The catalyst used is the metal … It is spread on to … Of a ceramic material to give it a large …
Platinum
Honeycomb
Surface area
Catalytic converters could not be used when … Was added to petrol as it poisons the catalyst. Ie when it reacts with the catalytic surface and renders it useless
Lead
Name two properties and uses of CO2
- soluble in water: carbonated for fizzy drinks as dissolves in water under pressure when the bottle is opened pressure falls and gas bubbles go out
- more dense than air: sinks on to flames and extinguishes as prevents oxygen to reach flame, fire extinguish to put out electrical fires or caused by burning liquids
Longer chained hydrocarbons are in what type of demand
Less
Hydrocarbon fuel burns in a gas lamp in a bowl of sand, gas collects in tube which travels to u-tube sitting in bowl of ice, bottom of u-tube contains blue cobalt chloride paper, gas goes out of u-tube into test tube of lime water and out to the water pump on the other side. What are the results and conclusion of this experiment
In u-tube we see condensation forming
The liquid formed turns cobalt chloride paper pink
Limewater turns cloudy
Hydrocarbon + oxygen –> carbon dioxide + water
Shorter chains from crude oil are more…
Useful
Ie gasoline
Even though longer chains from crude oil are less useful they are in ….
Higher abundance
Very large molecules of long chained hydrocarbons can be … Into … Smaller molecules. This process is called …
Split
Several
Catalytic cracking
Catalytic cracking is the process by which longer chain … Are broken down into more useful products
Alkanes
Cracking results in both … And … Production
Alkane
Alkene
Cracking is an example of a ….. Reaction
Thermal decomposition
Equipment used in a cracking experiment
- test tube horizontally with ceramic wool soaked in paraffin oil and in the middle a catalyst of porcelain chips
- delivery tube bases through the test tube to a tub of water with a safety valve on the end with a split
- test tube collects gas produced sitting on top of safety valve when oil is heated
In a cracking experiment the gas collected is called … The gas turns yellow bromine water …. The large … Molecules are … Down into smaller molecules. To do this we need a … Temperature and a … The … Molecules are more useful than the … Molecules
Ethene Colourless Paraffin Broken High Catalyst Small Large
What does a hydrocarbon contain
Only carbon and hydrogen
A homologous series are ‘Families’ of organic compounds (ie methane, ethane, propane which are all …), group of compounds which share similar … properties. differ from one another by a … and because they get larger they have a trend in … properties (like fractions in crude oil)
Alkanes
Chemical
CH2
Physical
Alkanes are a … In which all the bonds between carbon atoms are … Saturated compounds (no … or … bonds)
Hydrocarbon
Single
Double
Triple
General formula for an alkane is
CnH2n + 2
All carbons need .. Bonds
4
Monkeys Eat Peanut Butter Pancakes Happily
Methane - 1(carbon atoms) - CH4 (molecular formula) - CH4 ( structural formula, can work out from molecular formula) Ethane - 2 - C2H6 Propane - 3 - C3H8 Butane - 4 - C4H10 Pentane - 5 - C5H12 Hexane - 6 - C6H14
What are the 3 formulae for organic molecules
1) molecular formula: number of each sort of atoms in molecule
2) structural formula: shows how the atoms are bonded
3) displayed formula: shows how the atoms are bonded with a drawing
All carbons have 4 bonds except …
Graphite
Alkenes are … Hydrocarbons that contains a … Bond
Unsaturated
Double
General formula for alkene is
CnH2n
The position of the double bond in alkenes must be included in the name of the loner chains
Ie but-2-ene
But-1-ene
Only from ethene to hexene in alkenes as
Methene does not exist (cant carry a double bond)
How to test for alkanes and results
Add bromine water, doesnt go colourless from orange straight away, then put under UV light then will go colourless
What happens when an alkane in bromine water is put under UV light
A hydrogen bond is swapped with a bromine bond, this is called substitution. Results in bromo(methane) + hydrogenbromide
What happens when an alkene in bromine water is put under UV light
The double bond breaks, opening up sections where the bromine replace 2 previous hydrogen bonds, this is called addition, results in bromo(butane), except methane
How to test for alkenes and results
Put in bromine water and turns colourless from dark orange immediately
How to add an alcohol onto displayed formula
O - H
Or OH onto the other equations
What is meant when a molecule is saturated
Only has single bonds therefore cannot be an alkene
What is an isomer
The same molecules and bonds and formulae but different structures
What are the fractions of crude oil in order and at what temperature do they burn at (remember; really good kids deserve fat bagels)
- Refinery gases
- gasoline (20-200)
- kerosene (180-260)
- diesel (260-340)
- fuel oil (330)
- Bitumen N/A
How to name a structural formula
Number of carbon attached to name of branch - name of hydrocarbon route
How to find the structural formula to get it named
- count how many carbons are in the longest chain to find the root alkane
- find any branches on the chain, make sure the branch is attached to the lowest numbered carbon labelling carbons 1 - (4)
- count number of carbon roots in the chain to determine the beginning of the name of the compound
- the length and position of these chains is given in the molecules name
Polymer means
Many parts
What is a polymer
A chemical compound made of many, smaller, identical molecules (called monomers) linked together. Some are naturally occurring like cellulose
2 methods in which polymers are made
Addition polymerisation (just for alkenes) Condensation polymerisation
Addition polymerisation
Alkenes add to themselves
As addition proceeds further a long, a molecular chain is formed
The alkene is the repeating unit of the chain (the monomer)
The chain itself is the polymer
Eg if ethene adds to itself by breaking double bond, polymer turns into polyethene
Brackets on addition polymerisation show
The chain continues and repeats until the certain number of ‘n’
The 5 plastics in order
Polythene Polystyrene Polypropylene Polyvinyl chloride (PVC) Neoprene
Properties and uses of low density polyethene
Flexible and quite strong
Plastic bags, bottles
Properties and uses of polystyrene
Rigid and tough
Packaging
What is a monomer
Small alkene molecules
Condensation polymerisation does what
The addition of two different monomers releases a small molecule, usually water
Ethanol production - Industrial
Reactants
Ethene and steam
Ethanol production - Industrial
Temperature and pressure
High temperatures (300/330 degrees) High pressures (60-70 atm) Needs high input of energy
Ethanol production - Industrial
Catalyst
Phosphoric acid
Ethanol production - Industrial
Equation
CH2 = CH2(g) + H2O(g) –> CH3CH2OH(g)
Ethanol production - Industrial
Rate
Rapid
Ethanol production - Industrial
Quality of product
Produces much purer ethanol, very good quality, not many side resources
Ethanol production - Industrial
Use of finite resources
Once all the oil has been used up there wont be anymore
Ethanol production - Industrial
Process
A continuous flow process - a stream of reactants is constantly passed over catalyst, therefore more efficient than a batch process
Ethanol production - Industrial
Plant
Local oil supply as very costly to import and expensive to set up, needs constant monitoring but large scale reduces costs
Ethanol production - Industrial
Maintenance
Little maintenance once set up
Just needs observation
Ethanol production - Industrial
Labour
Low as little maintenance needed
Ethanol production - fermentation from sugars
Reactants
Glucose –> yeast and sugar solution
Ethanol production - fermentation from sugars
Temperature and pressure
Uses gentle temperatures (37 degrees for optimum enzyme function) and normal pressures (1 atm)
Ethanol production - fermentation from sugars
Catalyst
Enzymes in the yeast (zymase)
Ethanol production - fermentation from sugars
Equation
1) C12 H22 O11(aq) + H20(l) –> C6 H12 O6(aq) + C6 H12 O6(aq)
Sucrose + water –> glucose + fructose (isomers of each other)
2)C6 H12 O6(aq) –> 2C H5 OH(aq) + 2CO2(g) = ethanol
Ethanol production - fermentation from sugars
Rate
Slow, taking several days for each batch
Ethanol production - fermentation from sugars
Quality of product
Produces very impure ethanol that needs further processing
Ethanol production - fermentation from sugars
Use of finite resources
Renewable sources - sugar beet or sugar cane, corn and other starchy materials
Ethanol production - fermentation from sugars
Process
Batch process, everything mixed in reaction vessel then left for several days/weeks then fractional distillation for further purity
Batch removed and new reaction set up –> inefficient
Ethanol production - fermentation from sugars
Plant
Not very expensive not much monitoring needed as process is slower
Ethanol production - fermentation from sugars
Maintenance
A lot if maintenance with hygiene as bacteria etc
Ethanol production - fermentation from sugars
Labour
Very high as lots of maintenance needed
