6. organic chemistry 1 Flashcards
what is a hydrocarbon
compounds that only contain hydrogen and carbon
what is nomeclature
the set of rules about how organic compounds are named and how their formulas are represented
what is empirical formula
the simplest whole number ratio of atoms of each element in a compound
what is molecular formula
the true number of atoms of each element in a compound
what is general formula
all members of a homologous organic series follow a general formula.
for example:
alkanes general formula is CnH2n+2
what is structural formula
shows the arrangement of atoms within a molecule
what is displayed formula
shows every atom and every bond in an organic compound
what is skeletal formula
shows only bonds in a compound and any non carbon atoms.
each corner is a carbon atom and is it assumed hydrogens are bonded to them unless stated otherwise.
what is a homologous series
organic compounds that follow a general formula and react in similar ways. each consecutive member differs by CH2
what happens to boiling points as the length of organic compound chains increases
it increases
what is a function group
a group of atoms in a compound that allow molecules to be recognised as being able to react in a certain way because of their group
what is the function group of an alcohol and its IUPAC ending
-OH
ending: -ol
what is the function group of an phenol and its IUPAC ending
OH group off of a benzene ring
ending: phenol
what is the function group of an ether and its IUPAC ending
an oxygen group attached to a carbon and another atom
ending: ether
what is the function group of an aldehyde and its IUPAC ending
carbon double bonded to an oxygen and single bonded to a hydrogen
ending: - al
what is the function group of an ketone and its IUPAC ending
carbon double bonded to an oxygen and single bonded to another atom
ending: -one
what is the function group of a carboxylic acid and its IUPAC ending
carbon double bonded to an oxygen and single bonded to a OH group
ending: - oic acid
what is the function group of an ester and its IUPAC ending
carbon double bonded to an oxygen and single bonded to an oxygen thats bonded to another atom
ending : - ate
suffix of an alkane
-ane
suffix of an alkene
- ene
suffix of an alcohol
-ol
suffix of a carboxylic acid
-oic acid
suffix of a ketone
-one
suffix of an aldehyde
-al
suffix of an ester
-ate
suffix of an amine
-amine
prefix of fluorine functional group
fluoro-
prefix of chlorine functional group
chloro-
prefix of bromine functional group
bromo-
prefix of iodine functional group
iodo-
what is an addition reaction
the reactants combine to form a single product
what is a substitution reaction
one functional group is replaced by a different functional group
what is an oxidation reaction
a species loses at least one electron and is oxidised
what is a reduction reaction
a species gains at least one electron and is reduced
what is a polymerisation reaction
a reaction where monomers join together to form a long repeating molecule called a polymer
what do mechanisms show
movement of electrons
what are isomers
molecules with the same molecular formula but a different arrangement of atoms within the molecule
what are structural isomers
isomers that have the same molecular formula but a different structural arrangement of atoms. they can be straight chained or branched chains but will have the same molecular formula
what is a position isomer
isomers which have the functional group in a different position on the carbon chain
what is a functional group isomer
they have the same molecular formula but the molecules have a different functional group
what is stereoisomerism
they have the same structural formula but a different spatial arrangement of the atoms and bonds
what is E-Z isomerism
a type of stereoisomerisms that occurs due to the limited rotation around a double carbon bond.
what is an E isomer
where the same group is diagonally opposite the other
what is a Z isomer
where the same group are both either above or below the central atoms
what is the Cahn-Ingold-Prelog priority rules
the priority of different groups in molecules that can display E-Z isomerism.
the group on each side of the double bond with the higher Mr is given the higher priority.
how do cis-trans isomers differ from E-Z isomers
cis-trans isomers can only be used when there are hydrogen atoms to compare the two other groups to.
what is an alkane
a saturated hydrocarbon consisting of only single bonds and general formula: CnH2n+2
what is crude oil
a mixture of different hydrocarbons
how can crude oil be separated
using fractional distillation as the chain lengths of molecules are different and result in them having different boiling boils
how is crude oil separated:
1
2
3
- the mixture is vapourised and fed into the fractioning column
- vapours rise, cools and condense
- products are siphoned off for different uses.
where do short chain hydrocarbons end up in the fractioning column
at the top as they have lower boiling points so they rise higher up
where do long chain hydrocarbons end up in the fractioning column
at the bottom as they have higher boiling points so they dont rise as much.
what is cracking
breaking down longer chain hydrocarbons into smaller chain ones.
what is thermal cracking
cracking using high temperature and pressures to produce alkanes and alkenes. the reaction always forms an alkane and the remaining atoms form atleast 1 alkene
what is catalytic cracking
produced aromatic compounds with carbon rings. lower temperatures and normal pressures are used but a zeolite catalyst is needed to compensate for the lower conditions.
combustion of alkanes products
complete combustion with oxygen - carbon dioxide and water
incomplete combustion- carbon monoxide and water
by products-oxides, nitrogen and sulfur.
dangers of oxides as a byproduct of alkane combustion
in clouds the oxides react with water and form dilute acids which result in acid rain
how can oxides, nitrogen and sulfur be removed from the systems
using a catalytic converter with a rhodium catalyst
what is a biofuel
an alternative sustainable fuel source that produces and releases fewer, less harmful products when burned
why are biofuels used
the combustion of fossil fuels produces greenhouse gas cause global warming and contributing the climate change
example of a biofuel, how its produced and its properties
ethanol
produced by fermentation, enzymes break down starch from crops into sugar that can be fermented to form ethanol
it is carbon neutral as the carbon given out when burned it equal to the carbon take in by the crops during the growing process
how do alkanes react with halogens
in the presence of UV light to produce halogenoalkanes.
what are the three steps of free radical substitution for the chlorination of alkanes
- initiation - the halogen is broken down in the presence of UV light
CL2 -> 2Cl * - propagation - a hydrogen is replaced and the Cl* radical is reformed as a catalyst
Cl* + CH4 -> *CH3 + HCl
CH3 + Cl2 -> CH3Cl + Cl - termination - two radicals join to end the chain reaction and form a stable product
*CH3 + * CH3 -> C2H6
what is an alkene
an unsaturated hydrocarbon with at least one carbon- carbon double bond. have the general formula C2H2n
what is the carbon double bond an area of
high electron density
what bonds does the carbon double bond have
a normal covalent sigma bond and a pi bond
what can be used to identify an alkene double bond
bromine water as alkenes cause it to change colour from orange/brown to colourless.
this is because the double bond can open up to accept bromine atoms and become saturated.
are alkenes reaction
yes as the carbon double bond can open to form single bonds to other atoms
how to alkenes form alkanes
electrophilic addition with hydrogen. the C=C bond opens to form single bonds to each of the hydrogen atoms.
this requires a nickel catalyst.
can also be called a hydrogenation reaction.
how do alkenes react to form di-substituted halogenoalkanes
addition reaction with form halogens.
how do alkenes react to form mono-substituted halogenoalkanes
addition reaction with with hydrogen halides
how do alkenes react to form alcohols
addition reaction with steam
requires an acid catalyst e.g. phosphoric acid
how do alkenes react to form diols
oxidation with cold dilute acidified potassium manganate
what is electrophilic addition
a reaction mechanism that shows how electrophiles attack the double bond in alkenes.
what is an electrophile
electron acceptor that is attracted to areas of high electron density
what are addition polymers
produces from alkenes where the double bond is broken to form a repeating unit.
what are polymers
unreactive hydrocarbon chains with multiple strong, non polar covalent bonds which makes them useful for everyday products such as poly(ethene) shopping bags.
they are non biodegradable as addition polymers are unreactive.
how are polymers disposed of
as they are non biodegradable some are recycles, some are used as feedstock for cracking and some are incinerated however this produces toxic gases
how are halogenoalkanes polar
the halogens are more electronegative than the carbon atom. this means electron density is drawn towards the halogen forming positive and negative regions.
what are primary secondary and tertiary halogenoalkanes
primary - 1 alkanes group
secondary - 2 alkane groups
tertiary - 3 alkanes groups
how do halogenoalkanes produce alcohols
react with aqueous potassium hydroxide in a nucleophilic substitution
how do halogenoalkanes produce alkenes
react with ethanolic potassium hydroxide to produce alkenes in an elimination reaction
how do halogenoalkanes undergo hydrolysis
broken down with aqueous silver nitrate and ethanol.
the water acts as a nucleophile to break down the halogenoalkane releasing halide ions that react with silver ions to form silver precipitates.
how do halogenoalkanes produce amines
react with alcoholic ammonia to form amines in nucleophilic substitution
how do halogenoalkanes produce nitriles
react with alcoholic potassium cyanide in nucleophilic substitution
what is nucleophilic substitution
reaction mechanism that shows how nucleophiles attack halogenoalkanes.
what is a nucleophile
species containing a lone pair of electrons that is attracted to positive regions of molecules
can nucleophilic substitution occur for primary halogenoalkanes
yes
can nucleophilic substitution occur for secondary halogenoalkanes
yes
can nucleophilic substitution occur for tertiary halogenoalkanes
no
how can alcohols be produced
hydration and fermentation
what is a primary alcohol
alcohol connected to 2 hydrogens
what is a secondary alcohol
alcohol connected to 1 hydrogen
what is a tertiary alcohol
alcohol connected to no hydrogens
what is hydration
produced alcohols from alkenes in the presence of an acid catalyst e.g. phosphoric acid.
it occurs in aqueous conditions at 300 degrees under high pressures
what is fermentation
enzymes break down starch in crops to sugars which are fermented to form alcohols
alcohols combust in oxygen to form
carbon dioxide and water
how do alcohols react to form a halogenoalkane
react with halogenating agents via nucleophilic substitution
how to test for alcohols
react with PCl5 to produce a chloroalkanes which produces white steamy fumes that turn damp blue litmus paper red
how can alkenes be formed from alcohols
dehydration of alcohols where water is removed. concentrated phosphoric acid must be added as a reagent
how are aldehydes produced from primary alcohols
heated in the presence of acidified potassium dichromate.
get oxidised to aldehydes
distillation is required to separate the aldehyde product
how do primary alcohols produce carboxylic acids
heated under reflux where they oxidise further to carboxylic acids
how do secondary alcohols produce ketones
oxidised in the presence of acidified potassium dichromate
what is used to test the oxidation of primary and secondary alcohols
acidifies potassium dichromate goes from orange to green
how to test for aldehydes
benedicts solution.
add a few drops and gently warm the tube
if aldehyde is present red precipitate is formed
if aldehyde is not present the solution will remain blue
what is heating under reflux
continually heating the contents of the flask to allow reactions to occur.
a condenser helps to ensure the vapours condense and return to the flask for further heating.
what is a separating funnel used for
separating two mixtures with different densities
what is distillation used for
separating mixtures with different boiling points
what is drying
addition of an anhydrous salt to absorb moisture
what is boiling point determination
way of testing the purity of a sample. substance is packed into a thiele tube which has an inverted capillary tube then inserting it into a boiling point determination apparatus
