UNIT 3 - Year 1 Organic Chem Flashcards
what are the 5 features of a homologous series
- same functional groups
- same general formula
- similar chemical properties
- each successive member differs by CH2
- gradually changing physical properties
what is a hydrocarbon
a hydrocarbon is a compound made up of only carbon and hydrogen
what is a general formula
represents the homologous series of compounds using letters and numbers
what is a structural formula
shows how atoms are bonded to each carbon atom in a molecule
what is a displayed formula
representation of an organic comound and all its atoms and their bonds
what is a skeletal formula
formula with all the carbon adn hydrogen bonds assumed
what is a molecular formula
shows the number and type of each atom in a molecule
what is an empirical formula
the simplest whole number ratio of the elements present in a molecule
what is structual isomerism
the same molecular formula but a different structural formula
what are the 3 different types of structural isomerism and explain them
functional group- different functional groups
chain- different longest carbon chain length
position- functional/ alkyl group is on a different carbon
what is stereoisomerism
compounds with the same molecular and structural formula but atoms are arranged differently in space
what is geometric isomerism
have the same molecular and structural formula but the groups on the double bond can be switched above or below
what is an E isomer and what is a Z isomer
what does the difference between them cause in properties
an E isomer have functional groups on opposite sides of the double bond
a Z isomer have functional groups on the same side of the double bond
they hve very different chemical and physical properties
explain the process of fractional distillation
- it is carried out in a fractioning column which has a heat gradient at the top it is cool and at the bottom it is very hot
- crude oil enters the fractioning column and is heated so vapour rises
- vapours of hydrocarbons with low B.Ps will rise up the column and condense at the top to be tapped off and the fractions will high B.Ps will be at the bottom
what is the problem with fractional distillation (what does it miss)
crude oil contains small amounts of compounds containing sulphur and when burned it can form sulfur dioxide
what is the order of fractions in fractional distillation
- refinary gases
- petrol
- naptha
- kerosene
- gas oils
- mineral oils
- residue: wax, grease, bitumen
what is cracking and why do we use it
cracking is the breaking of long chain hydrocarbons into smaller ones as the smaller ones are more useful
what are the two types of cracking
what are the conditions
what are the products
thermal and catalytic
thermal- high temperatures and high pressure to produce alkanes and mainly alkenes
catalytic- lower temp and slight pressure in the presence of a zeolite catalyst to produce alkanes and aromatic hydrocarbons
what are the two types of combustion and what are the conditions and products of them
complete- in excess oxygen to produce CO2 and H20
incomplete- limted supply of oxygen to form CO,CO2,soot and H2O
what can car exhaust fumes contain?
carbon monoxide
nitrogen oxide
volatile organic compounds
how is nitrogen oxide produces in cars and what are the dangers of it?
high temperatures in the engine cause nitrogen to react with oxygen and nitrous oxides are released into the air
-they can dissolve and react with water to from nitric acid which causes acid rain
-they can also react with unburnt hydrocarbons to create VOCs which form smog
what is the role of catalytic converters and what is their structure
reduce the amount of pollutants released in car exhaust fumes
coated in a honeycomb structure of precious metals like: platinum,palladium and rhodium to increase the surface area
what is the equation/s for catalytic converters removing CO from the air
2CO + O2 –> 2CO2
or
2CO + 2NO –> 2CO2 + N2
what is teh equation for removiing nitrous oxides from the air in catalytic converters
2CO + 2NO –> 2CO2 + N2
what is the equation for removing unburnt hydrocarbons from the air in catalytic converters
hydrocarbon –> nCO2 + n+1H2O
what are the steps to free radical substitution
initation step: halogen bond is broken by UV light and forms 2 radical in homolytic fission
propagation step:radicals create firther radicals as they break the C-H bonds and form an alkyl radical and this can attack a halogen to from a halogenoalkane and regenerate the halogen radical
termination step: reaction is stopped when two radicals collids with each other
what happens in nucelophillic substitution and what are the products
halogen is subbed for another atom or group of atoms
either a alcohol, amine or nitrile is formed
what are the conditions for nucleophillic substitution to form an alcohol
aqueous solution of NaOH or KOH
or it can be with water but the reaction is very slow as there is only a partial charge whereas OH has a fully negative one
the mixture is warmed
what are the conditions of nucleophillic substitution with a cyanide
ethanolic solution of KCN heated under reflux
what is the product of nucleophillic substitution with a cyanide
produces a nitrile
what are the conditions of nucloephillic subsititution with ammonia
ethanolic solution of EXCESS ammonia heated under pressure
what is the product of nucleophillic substitution with ammonia
primary amine
what is elimination
when an organic molcule loses a small molecule and a double bond is formed
what are the conditions for elimination
ethanolic NaOH/KOH and reflux
what are the equations for chlorine reacting with ozone
Cl’ + O3 –> ClO’ + O2
ClO’ + O3 –> 2O2 + Cl’
overall equation is
2O3–> 3O2
what is electrophillic addition
the addition of an electrophile to a double bond turning a double bond into a single bond
what are the conditions for electrophillic addition with hydrogen
a nickel catalyst and heat
what are the conditions for electrophillic addition with steam
a H3PO4 catalyst and heat
what are the conditions for electrophillic with halides
room temp
how do you test for alkenes
add bromine water and it will go colourless
what 5 things can electrophillic addition happen with
hydrogen
steam
hydrogen halides
halogens
H2SO4
what is addition polymerisation
the reaction in which many monomers containing at least one double bond form a long chain moleucle that is made up of mamy repeating units
what is the most common polymer and what is it used for
PVC which are used to make plastics
how do you test for primary and secondary alcohols
- K2Cr2O7- acidified potassium dichromate added to oxidise alcohols
- primary and secondary go green and teritary stays orange
how can you test for the presence of an aldehyde
fehlings and tollens reagent
fehlings warmed with an aldehyde the aldehyde is oxidised into a carboxylic acid and the clear blue colour of the solution turns opaque red
tollens is warmed with an aldehyde and forms a carboxylic acid and a silver mirror is formed on the inside of the tube
what are the conditions for dehydration of alchohols
alcohol vapour passed over a hot catalyst of aluminium oxide powder or pieces of porous pot
what is IR spectroscopy
a technique used to identify compounds based on chages in vibrations of atoms when they absorb certain frequencies of IR
how does IR spec work
1.a spectrophotometer irradiates the sample with electromagnetic waves in the infrared region and then detects the intensity of the wavelength whcih goes through the sample
- all organic molecules absorb IR radiation and the radiation being absorbed will vibrate by stretching bending and twisting
3.the resonance freq. is the specific freq. at which the moleucles vibrate and the different functional groups have different vibration which is how you can identify them
