organics Flashcards
saturated vs unsaturated
saturated = max number of hydrogen bonds (alkanes)
unsaturated = contains double or triple carbon bonds which can be broken to add more hydrogen atoms
functional groups
specific groups of atoms within molecules that have their own properties and characteristics in a chemical reaction
homologous series
a series of compounds containing the same functional group, differing by only the number of carbon atoms in the chain
isomers
compounds with the same molecular formula but different arrangement of atoms
there is chain, position, and functional
requirements for geometrical isomers
- molecule is asymmetrical
- each carbon atom is bonded to two different atoms/groups of atoms
- there is a double bond to prevent rotation and fix the atoms in place
cis and kiss
properties of alkanes
saturated, single bonds only, relatively low mp and bp due to weak intermolecular forces.
alkanes with 1-4 carbons are gases at room temperature
alkanes are not polar, they are not soluble. they will form layers in water. they are also non-conductors due to electrons being fixed in covalent bonds
substitution reaction of alkanes
requires a halogen, Cl2 or Br2.
UV light catalyst required, the reaction is slow
hydrogen gas product
distinguishing test of alkanes and alkenes
add (MnO4)- or (Cr2O7)2- the alkane will form a layer on top and there is no colour change. the alkene will oxidise and go colourless
properties of alkenes
unsaturated, higher mp and bp due to its double bond which also makes it more reactive
hydrogenation of alkenes
hydrogen gas is added, the double bond is broken and an alkane is produced
conditions: Pt, at 150c
halogenation of alkenes
hydrogen halide or halogen gas is added to make a haloalkane
hydration of alkenes
water is added to produce an alcohol
conditions: H+ and heat
markovnikovs rule
the rich get richer
oxidation of alkenes
a strong oxidation will produce a diol
naming: butan-1,2-diol
colour change of (MnO4)- = purple to brown in the absence of acid
properties of alcohols
there is strong hydrogen bonding between the OH group and neighbouring alcohol molecules. it has a higher mp and bp than alkanes.
alcohols with 1-8 carbons are liquid at room temperature
solubility of alcohols
decreases as carbon chain increases
1-3C = very soluble
4C = soluble
5-6C = partially soluble
7+ C = insoluble due to large non-polar reigons
substitution of alcohols to produce a halogen
reagents = SOCl2, PCl3, PCl5
SOCl2 is a good reagent as HCl and SO2 product are gases. Liquid product is purely the haloalkane
nucleophiles
they are attracted to nuclei, positive charge. they have lone electron pairs / negative charge.
examples = Cl-, Br-, OH-, NH3, H2O
nucleophilic substitution of primary alcohols
reagent = NH3
produces an amine (NH2)
excess NH3 is required, the H from the amine (of the original NH3) produces NH4, producing NH4OH (ammonium hydroxide) as the OH is removed from the alcohol
conditions = heat
- this is to increase the rate of reaction and help particles overcome activation energy
nucleophilic substitution of tertiary alcohols
has 2 steps
- slow reaction which just removes the OH group producing a carbocation
- fast reaction where a nucleophile is attached. it is attracted to the carbon which the OH group was attached to due to its positive charge. must draw an arrow between the carbocation and nucleophile
conditions = heat is required for both steps
elimination of alcohols
alkene and water is produced
conditions = conc.H2SO4 or Al2SO3 and heat
conc.H2SO4 is a dehydrating agent
zaitseff’s rule
the poor get poorer
oxidation of primary alcohols
two steps
- distillation, an aldehyde is produced (C double bonded to H)
- reflux, a carboxylic acid is produced
conditions: H+ and heat
oxidation of secondary alcohols
a ketone is produced (C double bonded to O) hydronium ions and electrons are produced
unlike aldehydes, ketones cannot be further oxidised
oxidation of tertiary alcohols
cannot happen
- activation energy is too high
- carbon has max bonds already
properties of haloalkanes
almost insoluble, colourless, odourless, partially cloudy, less flammable than alkanes but more reactive, mostly liquid or solid at room temp
nucleophilic substitution of haloalkanes
- NaOH or KOH (aq) an alcohol is produced
conditions = reflux
- conc. ammonia (alc) produces an amine
conditions = heat (warm) and excess ammonia to produce ammonium
elimination of haloalkanes
conc. NaOH or KOH (alc)
alkene, water and halogen product
conditions = reflux
properties of amines
has hydrogen bonding and temporary dipole-dipole attractions between amine molecules, high mp + bp, slightly polar due to NH2 group, low molar mass amines are volatile liquids, high molar mass amines are solids at room temp
amine in water reaction
NH2 becomes NH3+ and an OH- is produced
how does an amine produce a salt
amines are bases so they react with acid to produce a salt
Ethylamine + HCl produces ethylammonium chloride.
H in HCl adds to amine and Cl is added after
Amine and CuSO4
produces a pale blue precipitate then a deep blue solution.
how to produce a secondary amine
add chloroalkane
H attached to amine is slightly positive and Cl in haloalkane is slightly negative. they produce HCl. Two new bonds are in each molecule so they combine together
what does HCl do after the production of secondary amines
they may react with the amine reactant to produce a salt
physical properties of carboxylic acids
weak acids, high mp and bp than alkanes of a similar molar mass, they have 2 functional groups
blue litmus goes pink
insoluble in water unless they have a low molar mass
water insoluble carboxylic acids are soluble in NaOH due to conversion of the acid to a carboxylate ion
hydrogen bonding between acid molecules which can produce a dimer
carboxylic acid behaviour in water
they partially dissociate
the H in COOH donates an H to H2O to produce H3O+
there is an equilibrium that is positioned to the left
carboxylic acids and metal
a salt is produced and hydrogen gas
ex. magnesium ethanoate
carboxylic acids and base
salt and water
acid and carbonate
salt, water, carbon dioxide
nucleophilic substitution of carboxylic acids
the OH group can be substituted to produce an acyl chloride with SOCl2, PCl3, PCl5
they can also produce an amide with NH3 (alc) but not haloalkanes
physical properties of esters
lower mp and bp than alcohols and carboxylic acids due to no hydrogen bonding
insoluble in water forming layers
distinctive odour, fruity
volatile
high mass esters are waxy solids with a less distinctive smell
what functional groups are isomers
carboxylic acids and esters
aldehydes and ketones
the slow way to produce an ester
esterification / condensation
requires: heat, reflux, conc. H2SO4 (dehydrating agent)
propanoic acid and alcohol
faster way to produce an ester
acyl chloride and alcohol
no conditions and higher yield. no catalyst or heat is needed
hydrolysis of esters in acid conditions
equilibrium reaction
splits ester back into alcohol and carboxylic acid
reagent: H2O/H+
hydrolysis of esters in basic conditions
creates alcohol and a salt (conjugate salt of the acid)
reagent: NaOH
conditions: conc. H2SO4
esterification of glycerol
stearic acid + glycerol (1,2,3 - propantriol)
heat, reflux, conc. H2SO4
esterification that produces soap
triglyceride is produced (a fat)
hydrolysis of triglyceride to produce soap
NaOH breaks the ester links in basic conditions. 3 fatty acid chains are produced which are ionic salts, soaps
this is saponification
glycerol is also produced
fat + acid -) soap and triol
physical properties of acid chlorides
OH group of carboxylic acids are replaced by a Cl
conc. HCl cannot be used to produce it as it would react with the acid chloride to produce a carboxylic acid
low mp and bp due to no hydrogen bonding
pungent fuming liquids
reactivity of acid chlorides
they are highly reactive due to the terminal carbon being bonded to two electronegative atoms. it is readily attacked by nucleophiles
hydrolysis of acid chlorides
rapid and violent
a carboxylic acid and HCl is produced. the Cl is replaced by OH
example of nucleophilic substitution
2 acids are produced, blue litmus goes pink
nucleophilic substitution of acid chlorides to produce primary amines
NH3 (alc) is required and replaces the OH group. excess is needed to produce NH4 combines with Cl to produce NH4Cl salt (ammonium chloride)
nucleophilic substitution of acid chlorides to produce secondary amines
primary amines react with acyl chlorides
the OH group is replaced by the NH2 group and joins the two molecules together
the H from the NH2 that joins to acid chloride is added to excess amine to produce a salt, the amine becomes NH4 at the end and Cl is added
why is NH3 (alc) used in substitution
because H2O is also a nucleophile and there would be competition
physical properties of amides
low carbon chain amines are soluble in water
neutral to litmus, they are not bases like amines
mp and bp is is high due to hydrogen bonding
only found on terminal carbon
how are amides produced
acyl chlorides with ammonia (much faster) or esters with ammonia
thermal decomposition of ammonium salt to produce amide
ammonium salt = CH3CH2COONH4 will react with heat to produce an amide and water
CH3CH2CONH2 + H2O
the O comes from hydroxy O and the 2H comes from NH4
hydrolysis of amides in basic/alkaline conditions
with NaOH
produces a salt and NH3
the Na and O produce salt and the H produces NH3
hydrolysis of amides in acid conditions
H2O and/or HCl (aq)
produces a carboxylic acid and NH3
With HCl, NH4Cl is produced alongside carboxylic acid
requires heat
describe enantiomers
enantiomers have the same physical properties such as solubility and melting point - they have the same atoms/groups of atoms. however, they rotate plane polarised light in equal but opposite directions - which non-optically active compounds cannot
requirements for an enantiomer
a chiral carbon. a carbon atom that is bonded to 4 different atoms/groups of atoms
racemic solution
a solution composed where both optical isomers are present equally. they cancel each other out when light is shone
