Chapter 11-15 Flashcards
Saturated hydrocarbon?
Unsaturated hydrocarbon?
Single carbon bonds only
Contains at least 1 carbon-carbon double or triple bond
Homologous series
Family of compounds with same functional group whose successive members differ by CH2
Functional group?
Part of organic molecule responsible for molecule’s chemical properties
Aliphatic meaning?
C atoms joined to each other in unbranched or branched chains or non aromatic rings
Alicyclic meaning
C atoms joined to each other in ring structure, with or without branches
Aromatic?
Some or all of carbon atoms found in benzene ring
Aldehyde functional group and name
C with double bond O, H and R group
-al
Ketone functional group and name
C double bond O and two R groups
-one
Uses of alcohol
Drinks
Fuel
Solvent
Ester uses
Flavour molecules
Solvent
Fragrance
Order for carbon alkyl group stem name
Eg meth-
First 10
Meth Eth Prop But Pent Hex Hept Oct Non Dec
Structural Isomer definition
Molecules with same molecular formula but different structural formula
3 types of structural isomer and explain
Chain: different arrangement of C skeleton, same functional grp
Positional: functional group attached to different C atom
Functional: contain different functional grp like aldehyde and ketones
What is a stereoisomer/ What type of isomer s
Does it have?
Definition?
Has E/Z isomerism
Same structural formula but different arrangement in space
What is a sigma bond, everything u know about it
Overlap of 2 atomic orbitals (s) directly in between nuclei of bonding atoms. It is a single bond.
Known as head on overlap
High bond enthalpy/requires lots of energy
What is a pi bond, everything you know
2 p orbitals overlap above and below internuclear axis known as sideways overlap
It requires low energy to break than sigma bond, low bond enthalpy
Not possible to rotate a pi bond about its axis, restricted rotation about the double bond
It is a region of high electron density
How can an alkene form stereoisomerism
If both C atoms on either side of double bond are attached to 2 different groups
What is cis trans
What is E/Z
Cis/trans if each of C in double bond has at-least 1 attached grp the same
E: enemy so opposite
Z: zame side or same
Cis is same side
Trans is opposite side
Priority rules for steroisomers
Assign priority to atom attached to C with double bond with highest atomic number
Or first difference in chain
Combustion of alkane products
Water and CO2 or CO
Shape and angle of alkane
Reason
4 bonding region so tetrahedral structure
109.5
Brief explain fractional distillation
Short chain low bp so top column as very volatile
Separation of different length hydrocarbons
Effect of chain length of hydrocarbon and bp
London forces between molecules in close surface contact. As chain length increases, molecules with larger surface area, more surface contact possible between molecules
Greater London forces so more energy required to overcome these forces and higher bp
Number of electrons increase so induced dipole dipole interactions increase
Radical substitution condition
UV light
Radical substitution stages
Initiation: UV radiation so homolytic fission of halogen forming 2 radicals
Propagation: radicals react with non radicals, chain reaction
Termination: radicals react with each other forming non radicals
Overall equation of radical substitution of methane and chlorine
CH4 +Cl2 —> CH3Cl +HCl
Radical substitution problems and why it is not used
Further substitution of compounds and formation of many positional isomers
Cant produce one specific product and unpredictable
Homolytic fission?
Heterolytic fission?
Each bonding atom receives 1 electron from the bonded pair of electrons
1 bonding atom received both electrons from bonded pair forming ions
Which molecule goes through electrophilic addition
Alkenes
Conditions and reagents of hydrogenation
Nickel catalyst
H2 gas
Alkene gas
Forms alkane
Test for alkenes
Halogenation at RTP
Bromine water: orange to colourless
As dibromoalkane formed
Addition of hydrogen halides method
HCl etc are gas at room temp so bubbled through liquid alkene or mix gases is alkene is gas
Also in solution in water as they are acids
Hydration reagents and condition
Steam and gaseous alkene heated in presence of conc phosphoric acid forming alcohol
Mechanism?
Sequence of steps showing the paths taken by electrons in a reaction
Electrophile?
Nucleophile?
An atom that is attracted to an electron rich centre where it accepts a pair of electrons
Species that donates electron pairs
What do curly arrows show
Movement of electron pairs which come from bonds, charges or lone pairs
Why are there major and minor products of electrophilic addition in unsymmetrical alkenes
General rule of major product
More alkyl groups in either side of carbocation is more stable for molecule
Major product is the one where you add H to carbon with most H attached to it already
What is a polymer?
Repeat unit?
Large molecules formed from lots of repeating u its of monomers
Small section of polymer that repeats continuously through structure
Formation of polymers from alkenes
Name of polymer
Pi bond breaks and link to other molecules
It is called polyalkene/monomer
Why are polymers not good for environment
Non biodegradable
How can polymers be disposed of instead of landfill
Recycled after sorting different types of polymers and can be then remelted/recycled
As fuel/incineration to generate energy
Feedstock recycling: used as raw material
Problems of PVC recycling/burnt
HCl gas produced which is toxic
Sustainable ways to replace polymers that are better for environment
Bioplastic/biodegradable polymers which can be broken down by microorganisms
Photodegradable polymer that contain bonds that weaken by absorbing light and start degradation process
Why do alcohols have lower volatility than corresponding alkane
Alcohols have hydrogen bonding that require more energy to overcome
Why are alcohols soluble in water
What happens as you increase chain length and why
Can form hydrogen bonding between polar hydroxyl group and water
Influence of OH group decreases so solubility decreases
What is a primary secondary and tertiary alcohol
It is about number of alkyl/R groups attached to carbon with hydroxyl group
Primary: 1 R group
Secondary: 2
Tertiary: 3
Oxidation of alcohol reagents and conditions
Primary alcohols: acidified dichromate (potassium dichromate and conc sulfuric acid). On gentle heating, oxidised to produce aldehyde, distill setup
On further heating and under reflux, further oxidised and excess acidified dichromate so 2[O] form carboxylic acid
Secondary alcohol: produced ketone under reflux
Tertiary: no reaction
How can you tell if an alcohol has been oxidised
Acidified dichromate changes colour from orange to green as it is reduced
What is reflux
Continual boiling and condensation of a solvent
Reagents and conditions of dehydration of alcohol
Heated under reflux in presence of acid catalyst
Product is alkene (can form isomers and stereoisomers) and water
Remove OH and H of neighbouring carbon atom
Halide substitution reagent and conditions
Alcohol heated under reflux with
H2SO4 and sodium halide so hydrogen halide formed in situ
The halide ion will react with alcohols and substitutes OH to form haloalkane and water
Overall equation of halide substitution of alcohols
Alcohol + NaBr + H2SO4 —> haloalkane + NaHSO4 + H2O
Explain nucleophilic substitution of haloalkane
Conditions
Electron deficient carbon atom as halogen is more electronegative so carbon is electropositive
The carbon attracts nucleophiles like H2O, OH- and NH3
Nucleophile replaces halogen in haloalkane. This is hydrolysis
Heat under reflux
What does rate of hydrolysis depend upon in haloalkanes
Bond enthalpy which decreases down halogens so carbon halogen bond easier to break and faster rate of reaction
How could you measure rate of hydrolysis of haloalkane into alcohol
Haloalkane heat with aqueous AgNO3, ethanol added as common solvent as haloalkane is insoluble in water
Water is nucleophile
Halide ions formed and then with Ag+ form coloured precipitates depending on halogen
Measure rate of formation of precipitates
Hydrolysis of haloalkane is faster in which?
Aqueous alkali or water
Alkali
Organohalogen compound uses
Refrigerants
Solvents
How is ozone formed
O2 with UV light forms 2 O
O2+ O reversible arrow to O3 which is ozone
How can you replace CFCs that is better for ozone protection
What does CFC stand for
HFC- hydrofluorocarbons
Chlorofluorocarbon
Overall reaction of ozone depletion by radicals
O3+ O —> 2O2
