C14 Flashcards
How does the prefix of a alkane/alkene/etc. Related to the number of carbon atoms?
Meth -> 1
Eth -> 2
Prop -> 3
But -> 4
After that Normal Greek prefixes
What are the formula and structures of:
Methane
Ethane
Ethene
Ethanol
Methane -> CH4
Ethane -> C2H6
Ethene -> C2H4
Ethanol -> C2H5OH
Structure -> check notes
What is a hydrocarbon?
A compound made of only hydrogen and carbon atoms
What is an alkane?
A saturated (only single carbon-carbon bonds) hydrocarbon
What is the formula for an alkane?
CnH2n+2
What are the characteristics of alkanes?
Generally unreactive
Do undergo combustion
Can be cracked -> catalytic cracking
What are isomers?
Alkanes that have the same formula, but a different arrangement
Naming isomers:
Find longest line (ex: propane)
Then nest line (ex: methane)
Find which carbon atom the second line connects to the first line -> REMEMBER: it can be MIRRORED (ex: 2)
2 methyl propane
What are alkenes?
Unsaturated (at least 1 carbon-carbon double bond) hydrocarbon
What is the formula for alkenes?
CnH2n
Why is there no such thing as methene?
Because you need at least 2 carbon atoms to form a carbon carbon double bond
Why are alkenes more reactive that alkanes?
The double bond can open to create more bonds, making it more reactive that alkenes
How are alkenes named?
By number of carbon atoms (prefix) and ending in -ene (suffix)
The funky ones:
Ex: but-1-ene
1 shows which bond between carbon atoms is the double bond -> REMEMBER: it can be MIRRORED
What are alcohols?
Hydrogen and carbon with one -OH group
What is the formula for alcohols?
CnH(2n+1)OH
How are alcohols named?
Prefix: number of carbon atoms
Suffix: -anol
Funkies:
Ex: propan-1-ol
Shows where the -OH group is -> REMEMBER: it can be MIRRORED
Draw the structure of alkanes and alkenes, up to 4 carbon atoms
Do it and check
What are coal, natural gas and petroleum/crude oil?
They are all fossil fuels
All contain carbon -> when burned -> carbon + oxygen -> combustion -> CO2
What is the main component of natural gases?
Methane
What is petroleum?
A mixture of hydrocarbons
Explain the separation of hydrocarbons in petroleum
Fractional distillation -> separated it into fractions (groups with similar chain lengths)
Molecules in each fraction -> similar boiling ponts
Fractional column: hot bottom and cool top -> each fraction condense at different temp/height -> smaller chain: top, bigger chain: bottom
What are properties of the molecules within a fraction?
Viscosity:
Attraction between molecules high -> more viscous
Longer-> more attraction -> more viscous
Color:
Longer-> darker color
Melt/boiling points:
Longer -> more attraction -> more energy required to separate -> high boiling/melting point
Volatility:
Tendency of a substance to vaporise
Longer -> more attraction less voliatile
What are the different fractions of petroleum?
In order from lowest -> highest boiling points
Refinery gas
Gasoline/petrol
Naphtha
Kerosene/paraffin
Diesel
Lubricant
Heavy fuel oil
Bitumen/paraffin wax
What are the uses of each fraction?
85% -> fuel for heating and transport
8%-> plastics and chemicals
Refinery gas:
Bottled gas for heating/cooking
Gasoline/petrol:
Fuel for cars
Naphtha:
Feedstock for chemicals and solvent
Kerosene/paraffin:
Jet fuel
Diesel:
Diesel engine/gas oil
Lubricant:
Used in products with moving parts
Heavy fuel oil:
Ships and power stations
Bitumen/paraffin wax:
Surfacing roads, waterproofing roofs, wax -> candles and waterproofing
What are properties of homologous series?
Compounds with:
Similar features + chemical properties
Same general formulas
Same functional groups
What are 2 examples of homologous series?
Alkanes and alkenes
What is the formula for complete combustion?
ex: methane
CH4 + 2 O2 -> CO2 + 2 H2O
Combustion results in CO2 and water
What is the formula for incomplete combustion?
Enough oxygen -> complete combustion
Not enough oxygen to burn -> incomplete combustion
CH4 + O2 -> C + 2 H2O
Results in CO and carbon particulates -> dangerous
What reaction to alkanes can be used to produce alkenes?
Cracking
What is cracking?
The process of converting long chain molecules (usually alkanes) into short chain molecules
Done because short chain molecules are more useful
Can create: shorter alkanes, alkenes, hydrogen
How is catalytic cracking done?
Heat to around 600-700°C -> compound vaporizes
Vapor passes over catalyst (Al3O2)
Breaks covalent bonds as the compound and catalyst come into contact -> thermal decompositions
How does demand make catalytic cracking useful?
Short chain molecules are more in demand, and by converting less in demand long chain molecules into shorter ones, we create a bigger supply of short chain molecules
How can you recognize a alkane or alkene from:
Molecular structure
Reaction with aqueous bromine
Molecular structure:
Double bond -> alkene
Only single bonds -> alkane
Reactions:
Aqueous bromine -> yellow/orange color
Lose color -> alkene
Same color -> alkane
What happens when bromine reacts with an alkene?
Ex: Ethene
C2H4 + Br2 -> C2H4Br2
Ethene + bromine -> dibromethane
Structure: bromine added across double bond
Hydrogen moved to sides
What happens when hydrogen reacts with an alkene?
Ex: ethene
C2H4 +H2 -> C2H6
Ethene + hydrogen -> ethane
Hydrogenation reaction -> done with a catalyst and high temps
What happens when an alkene reacts with steam?
Ex: ethene
C2H4 + H2O -> C2H5OH
Ethene + steam -> ethanol
SO:
Alkene + steam -> alcohol
Usually uses a catalyst (phosphoric acid) and high temp+pressure -> double bond broken and water joins
How is ethanol formed via fermentation?
Glucose -> ethanol + carbon dioxide
C6H1206 -> 2 C2H5OH + 2 CO2
Yeast -> fungus
without air -> anaerobic respiration -> yeast metabolises sugar
Ethanol removed via distillation
What is the product of complete combustion of ethanol?
C2H5OH + 3 O2 -> 2 CO2 + 3 H2O
Ethanol burns blue
What is ethanol used as?
Solvent:
Perfumes, cosmetics
Printing inks and glues
Fuel:
Mixed with petroleum or fuel for cars -> less polluting
Less reliance on petrol or diesel
What are polymers?
Long chain molecules formed by small units called monomers
What is (addition) polymerisation?
Monomers join to make polymers (monomer must have a double bond -> alkene) (polymer only has single bonds -> will join other building blocks )
Usually involves increased temp+pressure and a catalyst
Addition -> means it is an addition reaction -> double bond breaks and forms a bond with any adjacent monomer
What does the structure of a monomer or polymer look like?
Base:
Ex: ethene
Monomer: ethene -> has double bond
Polymer: poly(ethene) -> no double bonds, brackets, lines always go out of brackets (suggest it will connect to others of the same), n subscript -> number of building blocks
Describe the structure and name of a polymer that has 1 chlorine and another with 4 fluorine
Chloroethene -> one chlorine atoms in ethene structure-> becomes poly(chloroethene)
Tetrafluoroethene -> hydrogen replaced by fluoride in ethene structure -> becomes poly(tetrafluoroethene)
How can you convert repeat unit <=> monomer?
Monomer -> repeat unit:
Double bond -> single bond
Add bonds to achieve end (out of parentheses
Subscript on bottom right with number of units
Repeat unit -> monomer:
Single bond -> double bond
Remove side bonds
Subscript goes in front of monomer
What is condensation polymerisation?
2 monomers linked by the removal of a small molecule, usually water
What is the difference between between addition and condensation polymerisation?
Addition:
Forms only polymer molecules
Condensation:
Forms polymer molecules and one H2O molecule
How is nylon formed (condensation polymerisation)?
LOOK AT NOTES FOR A DIAGRAM
Nylon -> made from HOOCC2H4COOH (carboxylic acid) and H2NC2H4NH2 (diamine)
NOTE: notice how in the acid there are -COOH groups at both ends (mirror) and that same for the diamine with -NH2 groups (mirror)
OH (from acid) and H (from diamine) -> H2O (condensation polymerisation)
-> link created where they were -> nylon unit formed
When drawn -> unit mirror back and forth -> possible because the ends of the initial acid and diamine are mirrored
Filled in box -> carbon chain
Not filled box -> nitrogen chain
MAKE SURE THERE ARE ONLY N-N AND C-C BONDS AT THE ENDS OF THE UNITS
