Organic Chemistry Flashcards
What do all organis compounds contain?
Carbon
What are the first four alkanes?
Methane
Ethane
Propane
Butane
What is the homologous series?
A series of organic compounds that have the same functional group but with each successive member differing by CH2
What is a functional group?
A group of atoms responsible for the characteristic reactions of a compound
What do functional groups determine?
The pattern of activity
What does the homologous series determine?
The physcial properties
What is aliphatic?
Carbon atoms arranged in chains (unbranched + branched)
What is alicyclic?
Carbon atoms arranged in ring structures
What is the stem name for 5,6,7,8,9,10 carbon atoms?
Pent Hex Hept Oct Non Dec
What is the common prefix Cl?
Chloro
What is the common prefix Br
Bromo
What is the common prefix I?
Iodo
What is the common prefix OH?
Hydroxy
What is the common prefix CH3?
Methyl
What is the common prefix C2H5?
Ethyl
What is the common prefix C3H8?
Propyl
What is the common prefix C4H10?
Butyl
What is molecular formula?
The actual no. and type of atoms in a compound
What is empirical formula?
The simplest whole number ratio of atoms in a compound
What is skeletal formula?
These show the carbon chains and the major functional groups (not including the H’s)
What is displayed formula?
Shows how all the atoms are arranged and all the bonds between them
What is structural formula?
Shows the arrangement of atoms carbon by carbon, with the attachment hydrogens and functional groups
What is a structural isomer?
Molecules with the same molecular formula but different structural formula
What is a sterioisomer/geometric isomer?
Molecules with the same molecular formula, the same structural formula but a different spatial arrangement of atoms
What must a molecule ahve to be a sterio/geometric isomer?
Double carbon bond (non-rotating)
Each C must have 2 different groups attached
What type of isomer is it if the group are ACROSS from each other?
(trans) E
What type of isomer is it if the group is ADJACENT to each other?
(cis) Z
What is the Cohn-Ingold-Prelog name clature?
A more up to date system that gives priority to groups based on their atomic number
What does the higher atomic number mean?
The higher priority
What type of isomer is it when the 1 and 2 are across from each other? Cohn-Ingold-Prelog
E isomer
What type of isomer is it when the 1 and 2 are adjacent from each other? Cohn-Ingold-Prelog
Z isomer
What is homolytic fission?
When the covalent bond breaks, each atom receives one electron from the shared pair
What is heterolytic fission?
When the covalent bond breaks, one atom receives both electrons from the shared pair
What are radicals?
Very reactive molecules with single unpaired electrons
What does heterolytic fission form?
Ions
What are electrophiles?
A positive species which are able to accept a pair of electrons
What do electrophiles love?
Electrons
What is the symbol for a electrophile?
E+
What is a nucleophile?
A negative species able to donate a pair of electrons
What do nucleophiles love?
Nuclei
What is the symbol for a nucleophile?
Nu-
What is an example of a electrophilic addition?
Adding Br to ethene (addition reaction)
What is an example of nucleophilic substitution?
Adding OH to am alkane with Br (substitution reaction)
What are alkanes mainly used as?
Fuels to release energy
What is the general formula for an alkane?
CnH2n+2
What type of hydrocarbons are alkanes?
Saturated
What does the overlap of orbitals in alkanes lead to?
The formation of a sigma bond
What type of rotation is round a sigma bond?
Free rotation
What happens to the boiling point as you increase the chain length of alkanes?
It increases
Why does the boiling point increase as the chain length increases?
SA of interaction between molecules increases
Size of London forces increase
More energy needed to disrupt stronger London forces
So higher boiling point
What happens to the boiling point as the amount of branches increase?
It decreases
Why does the boiling point decreases as the number of branches increase?
SA of interaction between molecules decrease
Size of London forces decrease
Less energy needed to disrupt weaker London forces
So lower boiling point
Why are alkanes quite unreactive?
Since C-C + C-H bonds = strong
C-C bonds are non-polar
C-H bonds are virtually non-polar
What is the equation for complete combustion?
Alkane + oxygen —–> energy + water + carbon dioxide
What is the equation for incomplete combustion?
Alkane + oxygen —–> less energy + water + carbon monoxide
What order do you balance combustion equations?
C then H then O
What are the conditions needed for free radical substitution?
UV light
Halogen molecule
What is free radical substitution?
Homolytic fission
What are the three stages of free radical substitution?
Initiation
Propagation
Termination
What is the general formula for free radical substitution?
I - X2 = x. + x.
P - CaHb + x. = .CaHb-1 + Hx
CaHb-1. + X2 = CaHb-1x + X.
T - CaHb-1. + x. = CaHb-1x
What is the propagation stage?
A constant cycle
How is the constant cycle of the propagation stage stopped?
Till termination stage takes place
What does the termination stage involve?
Two radicals being added together
What are the problems with free radical substitution?
Further substitution
Can occur at different points in the carbon chain
What is the general formula for alkenes?
CnH2n
What is stronger a sigma bond or pi bond?
Sigma bond
What is a pi bond?
These are formed by the sideways overlap of two adjacent ‘p’ orbitals
LEARN DIAGRAMS FOR PI AND SIGMA BOND
LEARN DIAGRAMS
What is an addition polymer?
Formed when lots of small alkene monomers join together to form a long chain molecule called a polymer (no other products)
How do you draw a polymer?
Draw the monomer (single carbon bond)
Put brackets around
Extend arms out
Put ‘n’ outside bracket
What is HDPE?
High density poly(ethene)
What LDPE?
Low density poly(ethene)
Why does HDPE have a high melting point?
Straight chains
Packed tightly together
Strong forces between chains
Strong + tough material
Why does LDPE have a low melting point?
Branched chains
Not packed closely together
Weak forces
Weak + flexible material
What is hydrogenation of alkenes?
Using H2 to break the carbon double bond
What temperature do you need for hydrogenation?
150 degrees
What is the catalyst you need for hydrogenation?
Nickle
What is halogenation of alkenes?
Using Cl2 etc or HCl etc to break carbon double bond
What will happen if you carry out halogenation with two unsymmetrical reactants?
Produce two products
eg. 2-chloropropane and 1-chloropropane
What test do you use for saturation?
Bromine water test
What colour will bromine water go if it is positive?
Orange to colourless
What is hydration of alkenes?
Using steam (H2O) to break the double carbon bond to form an alcohol
What is the temperature needed for hydration?
300 degrees
What is the catalyst needed for hydration?
Phosphoric acid
LEARN DIAGRAMS FOR ELECTROPHILLIC ADDITION
LEARN DIAGRAMS
What does an electrophillic addition mechanism produce?
Carbocation (carbonium ion)
What is a primary carbonium ion?
Has only one C attached to ion
What is a secondary carbonium ion?
Has two C attached to ion
What do carbon centres have?
Inductive effect (I+)
What do I+ effects do?
Push electrodensity towards carbonium ion (C+) and stabilise it
What does it mean if there are more I+ effects?
More stable
What are the three types of carbonium ions?
Primary
Secondary
Tertiary
Which carbonium ion is the most stable ans why?
Tertiary because it has the most I+ effects
What is the major product?
The more favourable one which is the most stable and has the most I+ effects
What is Markownikoff’s rule?
The major product is produced when the negative part of the molecule joins to the carbon with the least number of attached H atoms within a double bond
What parts of recycling are polymers used in?
PVC recycling
Using waste polymers as fuels
Feedstock recycling
What is the advantage of recycling polymers?
It reduces their environmental impact by conserving fossil fuels + decreasing amount of waste
Why is it difficult to recycle polymers?
Because it is hazardous due to high chlorine content
Why can waste polymers be used as fuels?
Because they are derived from petroleum or natural gas so they have a high store energy value
What is feedstock recycling?
The chemical and thermal processes that reclaim monomers, gases or oil from waste polymers
Why is feedstock recycling good?
Products can be used as raw materials for the production of new polymers
What are bioplastics?
Alternatives to oil-based products that are produced from starch,cellulose and plant-oils to offer
What are photodegradable polymers?
Polymers that contain bonds that are weakened by absorbing light to start the degradation
What are biodegradable polymers?
Polymers broken down by microorganisms into water, CO2 and biological compounds
Why are compostable polymers good?
Because they degrade and leave no visible or toxic residue
What is poly(ethene) used in?
Plastic
What is polystyrene used in?
Cups, packaging + plastic cutlery
What is polytetrafluroethane (Teflon) used in?
Non-stick coating