Topic 10: Organic Chemistry Flashcards
What is an Alkane
Saturated hydrocarbons - composed of only carbon and hydrogens
Functional group of an alkane
alkyl
Order of increasing carbon names
methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane
General formula for alkane
CnH2n+2
Types of reactions that alkanes undergo
combustion reactions, free radical substitution
What is an alkene
unsaturated hydrocarbons, contains a carbon to carbon double bond
General formula of an alkene
CnH2n
Types of reactions that alkenes undergo
Combustion and electrophilic addition, can also undergo reduction reactions to produce alkanes
What is an alkyne
unsaturated hydrocarbons containing carbon carbon triple bond
General formula for alkyne
CnH2n-2
Reactions alkynes undergo
Combustion and electrophilic addition
What is an aldehyde
Carbon atom double bonded to an oxygen atom AND a single bond to a hydrogen
What is a carbon to oxygen double bond known as
carbonyl group
General formula of aldehyde
CnH2nO
How to name alkane
(root +) - ane
name alkene
- ene
name alkyne
- yne
name aldehyde
- al
Types of reactions aldehydes undergo
oxidation to form carboxylic acids
What is a ketone
Carbon atom double bonded to an oxygen atom AND bonded to two alkyl groups on either side
name ketone
-one
General formula of ketones
CnH2nO
Types of reactions that a ketone undergoes
Reduction (HL)
What is an ester
Carbon atom double bonded to an oxygen and ALSO single bonded to an oxygen, the single bonded oxygen is bonded to an alkyl group
Naming ester
One half is named after carboxylic acid, other side is named after alcohol. Base with ending -oate is the side attached to oxygen double bond
Name is two words with a space in between
Naming side groups is depending on the side its on, the numbers restart on when switching to different sides of the oxygen
General formula for an ester
CnH2nO2
What reaction forms an ester?
Condensation reactions between alcohols and carboxylic acids in warm sulphuric acid produces ester and water
hydrolysis reactions to form alcohols and carboxylic acids
What is an ether
Oxygen atom bonded to two alkyl groups
Naming ethers
The shorter side connected to the oxygen is the side chain named with -oxy (alkoxy substituent)
E.g. methoxy, ethoxy, propoxy, butoxy etc.
The longer alkyl group becomes the alkane stem
When there are more than 2 carbons in the alkane stem, use numbers to show which carbon the alkoxy substituent is connected to. e.g. 1-methoxy-4-methylpentane
General formula for ether
CnH2n+2O
What is an alcohol
OH bonded - hydroxyl group
naming alcohols
-ol
General formula for alcohols
CnH2n+2O
Types of reactions alcohols undergo
Combustion, oxidation, nucleophilic substitution with carboxylic acids to form esters
What is a carboxylic acid
Carbon double bonded to oxygen and a single bond to an OH
Naming carboxylic acids
-oic acid
General formula for carboxylic acids
CnH2nO2
Types of reactions carboxylic acids undergo
Nucleophilic substitution with alcohols to form esters
Nitriles
Carbon triple bonded to a nitrogen atom
Naming nitriles
-nitriles
General formula of nitrile
CnH2n+1N
Amine
alkyl group bonded to Nitrogen which is single bonded to to hydrogens - hydrogens can be replaced with alkyl groups depending on if its primary, secondary or tertiary
Naming amines
Amine, amino
General formula for amine
CnH2n+3N
Amide
Carbon double bonded to oxygen and a single bond to a nitrogen atom (which is also bonded to two hydrogens - these hydrogens can be changed for other alkyl groups)
General formula for amide
CnH2n+1NO
Phenyl
benzene molecule - minus a hydrogen and replaced with a substituent group
What is phenol
benzene with a hydrogen replaced with an OH group
Halogenoalkanes
alkyl bonded to a halogen
naming halogenoalkanes
fluoro- chloro- bromo- iodo-
General Formula for halogenoalkanes
CnH2n+1X
What reactions do halgenoalkanes undergo
nucleophilic substitution
what is a homologous series
series of organic compounds which differ by the same structural unit (methanol, ethanol, propanol, butanol) - have the same general formula
Chemical properties in homologous series
Are similar
Physical properties in homologous series
have a gradual increase in physical properties - such as boiling point
explain low reactivity of alkanes
The C-H bonds are non-polar, C-C and C-H bonds are quite strong
What is a cyclic alkane and what is its general formula
Alkanes in a ring CnH2n - add prefix cyclo-
Naming branched chain alkanes (kinda goes for most functional groups)
- identify longest carbon chain
- identify position of branches and give them the lowest number possible
- use prefixes di- tri- etc. if more than one of the same alkyl group is present
- put names in alphabetical order if there are more than one functional groups
e.g. 2, 2 - dimethylpropane / 2,3 - dipropylpentane
What are the rules for naming with di/iso/cyclo prefixes
di does not factor into alphabetical naming, iso does factor into alphabetical naming, cyclo factors in
Naming secondary amines
Use capitol N to show alkyl group is bonded to oxygen
e.g. N-ethylpropanamine
Structural formulas
Full structural formula (all atoms and bonds shown), condensed (only atoms shown, no bonds), skeletal (a literal line only showing carbon backbone)
Classifying alcohols
Number of carbon atoms directly bonded to the carbon atom which is bonded to the hydroxyl group (1 - primary, 2 - secondary - 3 tertiary)
Structural isomers
compounds with same molecular formula but diff arrangements of atoms
- differing in branches of carbons
- differing in position of double bonds
etc.
Factors affecting boiling points of organic compounds
- molar mass
- structure (straight chain vs branched chain isomers)
- type of functional group (hydrogen bonding, dipole dipole, london dispersion)
What is the polarity of alkanes - how does this affect its boiling point?
non polar - london dispersion forces between molecules, as molar mass increases - boiling point also increases (b/c # of electrons also increases and more to be induced and easily polarizable)
Boiling point in branched chain isomers vs straight chain
branched chain have lower bp because it prevents molecules from getting closer together –> therefore weaker london dispersion forces
Describe the london dispersion forces for all the functional groups
LDF: alkanes, alkenes, alkynes
Dipole-dipole: aldehydes, ketones, esters, ethers, nitriles
Hydrogen: alcohols, amides, amines, carboxylic acids
Boiling point trend in alkanes
As the chain length increases the boiling point increases, increases rapidly at first and then increase slows down.
Why does branching lower boiling point
Molecules become more spherical in shape, reduces surface area between them and lowers boiling point.
Why do alkanes have low reactivity
Have strong C-C and C-H bonds, low polarity.
Combustion of alkanes
Is exothermic because the double bonds of carbon and oxygen are stronger than the oxygen and hydrogen bonds. If there is insufficient amount of oxygen, incomplete combustion will occur and CO and C will also be products.
Halogenation reaction
Alkanes can react with halogens in the presence of ultraviolet light to form haloalkane and a substituted alkane. e.g. CH4 + Cl2 –> CH3Cl + HCl
essentially the Cl substituted the hydrogen
Describe heterolytic and homolytic fission
Heterolytic: when a chemical bond breaks, both the shared electrons go to one atom, resulting in neg and pos ions.
Homolytic: when chemical bond breaks the electrons are shared equally between two atoms, resulting in free radicals.
Two halogens (diatomic) can break homolytically in the presence of UV light.
Describe free radical chain reaction/substitution
initiation
propagation
termination
go look it up girl
Why are alkenes reactive
because of the carbon to carbon double bondl undergo electrophilic addition reactions
Hydrogenation of alkenes
double bond opens up and bonds with H2, needs high pressure, high temperature and a Ni catalyst to occur.
Halogenation of alkenes
Double bond opens up to accept halogens
Hydration reaction of alkenes
Alkene reacts with water (steam) in the presence of a sulfuric acid catalyst to form an alcohol.
double bond opens to accept a hydrogen and an OH.
How to test for unsaturation
Bromine water used, its a brown solution, when added to alkene the bromine water is decolourised, tells us its unsaturated. When added to alkane there is no colour change.
How are addition polymers formed
Formed when smaller unsaturated molecules react together.
Repeating unit of polymer notation
Showin with -(repeating unit)-n
value n is the amount of reapeating units
only happens in alkenes
What is the polymer polyvinyl chloride made from
The monomer unit chloroethene
Combustion of alcohols
React with oxygen to form CO2 and H2O
When does incomplete combustion occur
when reacting in a limited supply of oxygen
What does the primary oxidation of alcohols form
aldehydes and carboxylic acids
What is distillation
Used to seperate components of a mixture that have different boiling points.
Secondary alcohol oxidation reaction
Form ketones
What is reflux condenser
used to prevent loss of a solvent from a mixture, vapour rise up the column, condense and flow back down to the flask. `
What is nucleophilic substitution
Halogenoalkanes have a polar bond because of the halogen, halogen partial neg charge and carbon partial positive charge. They undergo nucleophilic substitution reactions. Nucleophiles which are electron rich species have long pair of electrons are attracted to electron deficient carbons in halogenoalkanes.
