Core Organic Chemistry Flashcards
Def Structural isomer
Molecules with the same molecular formula but different structural formulae
Def Homologous series
A series of organic compounds having the same functional group (+general formula) but with each successive member differing by characteristic due to additional CH2
Functional group
(Def not required)
A group of atoms responsible for the characteristic reactions of a compound
Alkyl group formula
CnH2n+1
What is aliphatic compound?
A compound containing carbon & hydrogen joined together in straight or branched chains or non-aromatic rings
What is alicyclic compound?
A compound arranged in non-aromatic rings with or without side chains
What is an aromatic compound?
A compound containing a benzene ring
Identification of carboxylic acid
(Functional group + naming)
F Group - COOH
Suffix - anoic acid
Ending = oic acid
Identification of amide
(Functional group + naming)
F group- RCONH2
Suffix- amide
Ending = amide
Identification of ester
(Functional group + naming)
F group- RCOOR
Prefix- alkyl. Suffix- anoate
Identification of haloalkane
(Functional group + naming)
F group- RX
Suffix-
Identification of aldehyde
(Functional group + naming)
F group - RCHO
Suffix- anal
Ending = al
Identification of alcohol
(Functional group + naming)
F group - OH
Suffix- anol
General formula of alcohol
CnH2n+2O
Genera formula of aldehydes?
+ how is it different from ketones
CnH2nO
Functional group at the end
General formula of ketones
+ how is it different from aldehydes?
CnH2nO
Functional group is found in middle of the molecule NOT at the ends
General formula of carboxylic acids?
CnH2nO2
General formula for amines
CnH2n+3N
General formula nitriles
CnH2n+1N
Prefix of named organic molecules shows?
The number of carbon atoms in the longest chain
(Meth, eth ,prop, but, pent ,etc)
Rule of numbering carbons in organic?
Number from the side which produces the lowest numbers
Order of steps to name organic molecules ?
Order of importance
1) find the longest C chain (root)
2) find the functional groups (ene, ol,al,one)
3) name any halogens in alphebetical order
4) any alkyl groups in alphabetical order
Stereoisomers def
Compounds with the same structural formula but the atoms are arranged differently in space
(Two catergories - geometrical & optical)
Difference in movement between double and single covalent bonds?
Single - fully rotational
Double- very restricted rotation= can flex slightly but not rotate like single bonds
Conditions needed for cis (Z)/ trans (E) isomers? (Stereoisomers)
1) C atoms at either side of double bond must be attached to two different groups.
Due to restricted rotation of C=C bond groups either side are fixed unlike in single C-C bonds where they can rotate.
2) at least on of those groups must be the same on the C atoms
Which molecules is cis/ trans in stereoisomers
Look at the group which is the same on both carbons either side of double bond
Cis
- if these two atoms are on the same side of carbon atoms
Trans
- if these two atoms are on opposite sides of carbon atoms
Different types of covalent bond fissions? +what makes them different?
-
Homolytic fission (Homolysis)
Each bonding atom receives one electron from the bonded pair
[equally split = two radicals] -
Heterolytic fission (Heterolysis)
One bonding atom receives both electrons from the bonded pair
[unequally split]
What are radicals + how they are shown?
Radical - a species with an unpaired electron
Large dots are used after the element/molecule to show the unpaired electron
What is use to describe movement of an electron pair?
In heterolytic fission/ formation of a covalent bond
A ‘curly arrow’ is used
Describe the mechanism of Methane and Chlorine in radical substitution
Conditions requires : UV light
Mechanism:
INITIALTION. Cl2 —> 2 Cl .
PROPAGATION Cl. + CH4 —> CH3. + HCl
Cl2 + CH3. —> CH3Cl + Cl.
TERMINATION. Cl. + Cl. —> Cl2
Cl . + CH3. —> CH3Cl
CH3. + CH3. —> C2H6
In chlorination of methane reaction ( mechanism) what are the steps? + why are they these?
Initiation
- a molecules is broken up into two radicals
E.g. Cl2 —> 2Cl.
Propagation
- radicals used and regenerated
Termination
- 2 radials from a complete molecule
Structure off Alkenes?
- unsaturated hydrocarbons constraining C=C bond comprising of a pi bond and σ bond ; the molecule has restricted rotation due to pi bond.
what is pi bond?
Pi bond
- sideways overlap of adjacent p-orbitals above and below the bonding C Atoms
What is sigma bond?
Sigma bond
- overlap of orbital directly between the boding atoms
(This is the one ins single bonds)
Difference between Cis/ trans isomers and E/Z isomers
Cis/trans
special case of E/Z isomerism with 2 of the substituent groups attached to each carbon atom of the c=c groups are the same)
-only used when 2H and 2 non-hydrogens on C=C bond
E/Z
example of stereoisomerism requires 2 different groups to be attached to each carbon atom of the C=C group
- can be used at all times but uses higher priority groups using CIP priority
CIP priority of atoms/groups for E/Z isomers
I > Br > Cl > F > H
C3H7 > C2H5 > CH3 > H
Prioritised according to their mass number
Higher mass number = higher priority
arrangements and bond angle of atoms around C=C in Alkenes
Arrangement = trigonal planar
Bond angle = 120o
As electron pairs repel each other appart
Why are alkenes more reactive than alkanes?
Alkenes are highly reactive due to relatively low bond enthalpy of the π bond
electrophilic addition reaction
Alkenes + hydrogen
1) reagent
2) conditions
3) equation
4) use
1) hydrogen
2) nickel catalyst - finely divided
3) C2H4(g) + H2 (g) —> C2H6 (g)
4) produces Alkenes and is used in margarine manufacturing
electrophilic addition reaction
Alkenes + bromine
1) reagent
2) conditions
3) equation
4) mechanism
5) use
1) bromine water or dissolved in tetrachloromethane (CCl4)
2) room temperature
3) C2H4(g) + Br2(g) —> CH2BrCH2Br(l)
4) see notes
5) bromine used to detect presents of double C=C bond as a test for unsaturated hydrocarbons because changes colour from orange to colourless
electrophilic addition reaction
Alkenes + hydrogen halides (e.g HBr)
1) reagent
2) conditions
3) equation
4) mechanisms
5) use
1) hydrogen bromine
2) room temperature
3) C4H4(g) + HBr(g) —> C2H5Br(l)
4) see notes
5) to from haloalkanes
type of fission occurs in electrophilic addition?
Heterolytic fission
(Uneven distribution)
Def of electrophiles
An atom/ group of atoms that is attracted to and accepts an electron pair.
(Usually positive ion)
What do curly arrows show in mechanisms
The reaction mechanism to show movement of electron pairs
Explain Markownikoff’s rule to predict formation of major/minor products from addition reactions with alkenes (unsymmetrical)
Major products formed when more important group is on more stable carbocation.
More stable carbocations have more carbons bonded to them.
E.g 1 c-c primary
2C-c secondary
3C-c tertiary (most stable)
Show formation of π bond
See notes
Adv/disadv of processing waste polymers via combustion
Adv
- saves on landfill sites
- releases energy that can be used to generate electricity
Disadv
- toxic fumes (HCl) are produced
Adv/disadv of processing waste polymers via feedstock
Adv
- feedstock recycling is able to handle unsorted & unwashed polymers
- can be used to produce new polymers
Adv/disadv of processing waste polymers via recycling
Adv
- saves on raw materials
- decreases amount in landfill
- thermoplastic polymers can be melted down &re-shaped
Disadv
- have to be sorted by type of polymer
- energy and resources needed to collect and sort waste as well as wash and melt
- can be more expensive
Ways waste polymers can be processed sustainably
- recycled
- feedstock
- combustion for energy production
2-chloropropene can be polymerised to form poly(2-chloropropene).
I) write a balanced equation for the for formation of this polymer, equation should include structure of repeat unit of polymer
see notes
Ensure that n is seen on both sides
Describe the differences between the σ bond and π bond
(3 main)
1) π bond has a lower bond empathy
2) π bond has sideways overlap whereas σ bond is direct overlap of s-orbitals
3) σ bond is between bonding atoms whereas π bond is above and below bonding atoms
Explain why a compound may not have E/Z isomer but still has double bond
1 of the carbon atoms is attached to two groups which are the same.
Radical substitution produces a mixture of organic products
Suggest 2 reasons why
- produces different termination products
- substitution at different points along the chain
Suggest why 2-methylbut-2-ene is less soluble in water than isomers of C5H12O
2-methylbut-2-ene
-doesn’t contain OH group (not an alcohol)
- doesn’t therefore form H bonds with water
How is hydrogen chloride gas removed from waste gases
+with what
It is neutralised with NaHCO3 (sodium hydrogencarbonate)
Structure of phenol
An aromatic hydrocarbon with an OH group directly attached to a benzene ring
Compare Boiling points of alcohols and alkanes
+ explain why
Alcohols = higher boiling point
Reason = inter molecule hydrogen bonds present as well as induced dipole dipole interactions
Trend of alcohol solubility
As increase the C atoms in alkyl group
Shorter alcohol chains are miscible with water due to hydrogen bonds
As you increase C chain solubility decrease as larger area of non polar region that cannot be dissolved
Draw example of primary, secondary, tertiary alcohol
See notes
Primary- one other carbon bonded to central carbon (with OH attached)
Secondary - two other carbons bonded to central carbon (with oH attached)
Tertiary - three other carbon atoms boned to central carbon (with OH attached
Way to produce alcohols
1) two industrial methods
2) in lab from -Haloalkane
- aldehydes
industrially
fermentation
- uses glucose and yeast in warm conditions to produce alcohol and CO2
direct hydration
- alkene + acid. Catalysed (phosphoric acid) +steam produces alcohols
in labs
from haloalkanes
- reflux with aq sodium/potassium hydroxide
from aldehydes
- reduction with sodium tetrahydridoborate (NaBH4)
Products of oxidation of primary alcohols? + give example of equation
If distilled = aldehyde
E.g CH3CH2OH (l) + [O] —> CH3CHO (l) + H2O (l)
If refluxed = carboxylic acid
E.g CH3CHO (l) + [O] —> CH3COOH (l)
Products of oxidation of secondary alcohols? + give example equation
Ketones
E.g CH3CHOHCO3 (l) + [O] —> CH3COCH3 (l) + H2O (l)
Products of oxidation of tertiary alcohols
They are not oxidised under these conditions. They do break down with vigorous oxidation though.
Describe the hydrolysis of haloalkanes in substitution reaction bu aqueous alkali
(Mechanism)
See notes
Remember
-dipoles on C and halogen
- lone pairs on OH- group
- curly arrows moving towards were electrons are moving
Define nucleophile
An electron pair donor
Nucleophilic substitution mechanism
Reagents-
Conditions-
Mechanism-
Formula-
Explain trend in rate of hydrolysis of primary haloalkanes
Bond enthalpies …
Identification of Ketone
(Functional group + naming)
Functional group= C=O attached in the middle of chain
Ending = one
