polymerisation Flashcards
what si a polyester
it has an ester monomer repeated over and over - joined by condensation reactions
how is an amide formed
when a carboxylic acid and amine join
why is kevlar so strong
rigid chains and the ability of the planar benzene to pack together held together by vdw foa.
why are polyethene and polypropene not biodegradable
they have strong non-polar C-H and C-C bonds. there is nothing in the natural environment that will easily break them down
why do amino acids have high melting points
they are ionic - within their zwitterion there is a strong dipole therefore strong electrostatic forces of attraction
can amino acids dissolve in water
yes - but VERY poorly in non-polar solvents
how will an amino acid behave in strongly acidic conditions
the lone pair on the NH2 will become protonated
how will an amino acid behave in strongly alkaline conditions
the OH- looses a proton
the carboxylic group becomes deprotonated
which amino acid shows optical isomerism
alanine
how can an amino acid display optical isomerism
there is an equal possibility of attack above an below the plane of c=o. plane polarised light is able to rotate in an equal ration to show no change in the racemic mixture.
what does an acid and a base make
a salt and water
what is the functional group of an ester
coo
what is a plasticizer
allows compounds to become more flexible - the ester will push polymers apart and weaken bond s
what are common uses of esters
perfumes, food flavouring, solvents AND plasticisers
di esters have a high or low bpt
low
what is the density of esters like
less dense than water
are esters immiscible
yes
what are the products when an ester is hydrolysed with HCl
carboxylic acid and alcohol
what are the products when an ester is hydrolysed with NaCl
carboxylate salt and an alcohol
what type of esters are fats and oils
tri-esters
how many fatty acids do glycerol have
3
why are fatty acids insoluble
they have massive r groups - water can not get in and dissolve the fatty acid. the fatty acids are non polar and the predominant foa is vdw
what are the intermolecular foa between fatty acids
there is a lot of contact between molecule so the IFOA is strong
what is the strength like in an unsaturated fatty acid
weak - they cannot get close - vdw is weak
