B3 Organic Chemistry I Flashcards
How are two numbers seperated in organic nomenclature
Comma
How are numbers and letters seperated in organic nomenclature
Dash
Which carbon number does the highest priority functional group get
The lowest carbon number
Where there are the same priority groups, which group gets the lowest carbon number
First group alphabetically
General formula of alkyl groups
Six carbon prefix
Hex
Seven carbon prefix
Hept
Nine carbon prefix
Non
Ten carbon prefix
Dec
Define empirical formula
The simplest whole number ratio of atoms of each element present in a compound
Define molecular formula
The total number of atoms of each element present in a molecule
Define homologous series
- A series of organic compounds with the same functional group
- But with each successive member differing by CH2
What is an aliphatic compound
- Contains hydrogen and carbon atoms
- Joined in a straight chain, branched chain, or non-aromatic ring
What is an alicyclic compound
- An aliphatic compound
- Arragned in non-aromatic rings
- With or without side chains, but no benzene ring
What is an aromatic compound
Contains a benzene ring
How are benzene rings drawn
Relationship between compounds being alicyclic and aliphatic
- All alicyclic are aliphatic
- Not all aliphatic are alicyclic
What is a saturated compound
Contain single carbon-carbon bonds only
What is an unsaturated compound
Contain multiple carbon-carbon bonds
Define structural isomers
Compounds with the same molecular formula, but different structural formulae
Define homolytic fission
Each bonding atom recieves one electron from the bonded pair, forming two radicals
Define heterolytic fission
One bonding atom recieves both electrons from the bonded pair, forming an ion
Define radical
A species with an unpaired electron
Define Curly Arrow
The movement of a pair of electrons, showing either heterolytic fission, or the formation of a covalent bond
What is the only type of covalent bond present in alkanes
Sigma bonds
Why do alkanes have a low reactivity
- High bond enthalpy of the C-H and C-C bonds
- Low bond polatiry of the C-H and C-C bonds
General formula of alkanes
General formula of cyclic alkanes
What bonds will be present in a single covalent bond
A sigma bond
What bonds will be present in a double covalent bond
One sigma bond, one pi bond
Ways to comapre sigma and pi bonds
- Orbital overlap
- Bond enthalpy
- Electron density
- Rotation
What bonds will be present in a triple covalent bond
One sigma bond, two pi bonds
Sigma vs Pi: Orbital overlap
- Orbitals overlap directly between bonding atoms in sigma
- Sideways overlap of adjacent p-orbitals above and below the bonding atoms in pi
Sigma vs Pi: Electron density
Sigma have a much higher electron density than pi bonds
Sigma vs Pi: Rotation
- Sigma have free rotation
- Pi have restricted roation
Sigma vs Pi: Bond enthalpy
- Sigma have a higher bond enthlapy so are stronger
- Pi have a lower bond enthalpy so are weaker
- More energy is requred to break sigma bond than pi bond
Explain why a longer carbon chain alkane has a higher boiling boint than a shorter carbon chain alkane
- Longer carbon chain means larger surface area for contact of London forces acting between molecules
- London forces therefore stronger
- More energy required to break London forces
Explain why the more branched an alkane’s carbon chain is, the lower it’s boiling point
- More branched carbon chain means smaller surface area for contact of London forces acting between molecules
- Weaker London forces
- Less energy requreid to break London forces
Word equation for alkane complete combustion
Word equation for alkane incomplete combustion
Produces Carbon Monoxide which is toxic
Why is alkane incomplete combustion hazardous
Produces carbon monoxide which is toxic
What condition is required for Free Radical Substitution and why
- UV Light
- Provides energy to break covalent bond (homolytic fission)
Free Radical Substitution: initation step for chlorine and butane
Free Radical Substitution: propagation steps for chlorine and butane
Free Radical Substitution: Termination steps for chlorine and butane
Why is Free Radical Substitution limiting to produce a desired product
- Substitution can replace any hydrogen atom in any position along carbon chain
- Further substitution can occur
- There is more than one termination step, so more than one termination products
General formula for alkenes
Functional group of alkenes
C=C bond
Why are alkenes very reactive
The pi bond in the C=C bond has a low bond enthalpy
Draw a labelled diagram of a pi bond
Define stereoisomers
Compounds with the same structural formula, but with a different arrangement in space
When can E/Z isomerism occur in alkenes
When each carbon involved in the C=C bond, has two different groups bonded to it
When would an alkene not have steroisomers
If one/both the carbons involved in the C=C bond has two of the same groups attached
In stereoisomerism, how do you decide on priority groups
Group with highest atomic number
How to explain if an alkene is an E isomer
- X is priority group over Y on left hand side carbon involved in the C=C bond
- A is priority group over B on the right hand side carbon involved in the C=C bond
- Prioritry groups are on opposite sides
How to explain if an alkene is a Z isomer
- X is priority group over Y on the left hand side carbon involved in the C=C bond
- A is priority group over B on the right hand side carbon involved in the C=C bond
- Priority groups are on the same side
When can Z-isomers be reffered to as cis isomers
As long as there is a hydrogen on each carbon atom of the C=C bond
When can E isomers be reffered to as trans isomers
As long as there is a hydrogen on each carbon atom of the C=C bond
Define electrophile
An electron pair acceptor
What type of reaction is alkene to alkane
Electrophillic addition
Conditions and reagents for alkene to alkane
- Hydrogen
- Nickel Catalyst
Displayed formula equation for ethene to ethane
Type of reaction for alkene to halogenoalkane
Electrophillic addition
How are alkenes tested for
- Add bromine water
- Will be decolourised
Mechanism for bromine + ethene
Reagents and conditions to turn alkene to alcohol
- Phosphoric acid catalyst
- Steam
Displayed formula equation for alkene to alcohol
What is the most stable carbocation
Tertiary
What is the least stable carbocation
Primary
Primary Carbocation
Secondary carbocation
Tertiary carbocation
In alkene reactions with hydrogen halides, to which carbocation will the hydrogen to go
The least stable
In alkene reactions with hydrogen halides, to which carbocation will the nucleophile (halogen) to go
The most stable carbocation
Draw the mechanism for an alkene reaction with hydrogen halide, including both major and minor products
Explain the three ways in which addition polymers can be destoryed
- Combustion - releases lots of energy for electricity
- Organic feedstock for production of other polymers
- Recycling
Displayed formula equation for addition polymerisation of ethene
Why is combustion of addition polymers an issue
- Results in formation of HCl and CO
- Which are toxic
How can HCl be removed as a product from combusting addition polymers
Passing it through an alkali
Why are biodegradeable and photodegradable polymers more beneficial to the enviroment
- As they don’t need to be incinerates
- So there is no formation of HCl and CO
- Which are toxic
What is the functional group of the alcohol homologous series
-OH (hydroxyl)
Alcohol general formula
Primary alcohol
Secondary alcohol
Tertiary alcohol
Describing primary alcohol
If the carbon the -OH group is bonded to has two hydrogens bonded to it
Describing a secondary alcohol
If the carbon the -OH is bonded to has one hydrogen bonded to it
Describing tertiary alcohol
If the carbon the -OH group is bonded to has no hydrogens bonded to it
Why are alcohols soluble
- They contain an -OH (hydroxyl) group
- The -OH group can form hydrogen bonds with the water
Why do alcohols have higher boiling points than other homologous series
- They contain an -OH (hydroxyl) group
- The -OH group can form hydrogen bonds with other molecules
- More energy is needed to break the hydrogen bonds than the London Forces in other homologous series
Conditions, reagents and observations for primary alcohol oxidation to aldehydes
- Potassium dichromate
- Sulfuric acid
- Heat and distill
- Potassium dichromate will turn orange to green
Conditions, reagents and observations for primary alcohol oxidation to carboxylic acid
- Add pottassium dichromate
- Sulfuric Acid
- Heat under reflux
- Potassium dichromate will turn orange to green
Structural and displayed formula equation for primary alcohol oxidation to aldehyde
Suffix for aldehyde
-anal
Structural and displayed formula equation for primary alcohol oxidation to carboxylic acid
Conditions, observations and reagents for secondary alcohol oxidation to ketone
- Potassium dichormate
- Sulfuric Acid
- Heat under reflux
- Potassium dichromate will turn orange to green
C=O group name
Carbonyl
Ketone suffix
-one
Strucutral and displayed formula for alcohol to ketone
What is the way in which tertiary alcohols must be oxidised
Combustion
Word equation alcohol complete combustion
Word equation alcohol incomplete combustion
Why is incomplete combustion of alcohols hazardous
Produces carbon monoxide which is toxic
Reagents and conditions for alcohols to alkenes
- Phosphoric acid
- Heat
Why is there only one possible product of primary alcohol elimination to alkene
The C=C bond can only from from one carbon
Displayed formula equation primary alcohol elimination to alkene
Why will secondary and tertiary alcohols be able to produce multiple products, and what will they be
- The C=C bond can form from two carbons
- They could have E/Z isomerism
Conditions and reagents for alcohol to haloalkane
- Sodium halide
- Sulfuric acid
What type of reaction is alcohol to haloalkane
Nucleophillic Substitution
Displayed formula equation for alcohol to haloalkane
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Type of reaction from haloalkane to alcohol
Nucleophillic substitution
Conditions and reagents for haloalkane to alcohol
- Warm NaOH
- Acid catalyst (sulfuric acid)
- Heat under reflux
Mechanism for nucleophillic substiution of haloalkane to alcohol
Define nucleophille
An electron pair donor
How to measure reactivity of haloalkanes experementally, and result
- Add AgNO3 and ethanol
- The iodo-compound will take the shortest time to form a precipitate
Describe and explain the reactivity of the haloalkanes
- C-Cl bond is strongest, then C-Br bond, then C-I bond is weakest
- C-Cl bond has higher bond enthalpy, then C-Br bond, then C-I bond has lowest
- More energy is required to break the C-Cl bond than the C-Br bond
- More energy is required to break the C-Br bond than the C-I bond
What is a CFC
A molecule containing, carbon, flourine and chlorine
What are the primary properties of CFCs
- Non-toxic
- Volatile
- Low reactivity
What is the function of the ozone layer, and what equation shows how ozone’s concentration is maintained
Absorbs UV radiation, so that UV levels at the Earth’s surface are reduced
What happens to CFCs in the presence of UV radiation
They can produce radicals
What acts as a catalyst in the breakdown of the ozone layer
Chlorine radicals and nitrogen oxide radicals
Initiation stage for ozone breakdown
Propogation stages for ozone breakdown
Overall equation for ozone breakdown
How are nitrogen oxides created
Thunderstorms and aircraft
Equations to show how nitrogen oxide radicals breakdown ozone
Order of practical techniques to purify a substance
- Heat under reflux or distil
- Seperation
- Drying
- Re-distillation
Benefit of heating under reflux
Prevnts any substances escaping
Benefit of distillation
Can control a reaction by removing a product before it further reacts
Labelled diagram of heating under reflux
Labelled diagram of distillation
Describe purification by seperation if organic layer is less dense than aqueous layer
- Use a seperating funnel
- Remove bottom layer
- Keep desired top organic layer
- As organic layer less dense than aqueous layer
Describe purification by seperation if organic layer is more dense than aqueous layer
- Use seperating funnel
- Remove desired bottom organic layer
- As organic layer more dense than aqueous layer
Describe purification by drying
- Add anhydrous salt to organic layer
- Such as anhydrous CaCl2 or anhydrous MgSO4
Describe purification by redistillation
- Redistill
- Collect fraction distilling at XYZc
Define a Functional Group
A group of atoms that is responsible for the molecules chemical properties and reactions
