carboxylic acids/ esters/ polymers Flashcards
functional group- carboxylic acid
COOH
general formula - carboxylic acid
CnH2n+1COOH
how to make carboxylic acids
made by oxidation of alcohols
eg ethanol oxidised to ethanoic acid
ethanol oxidation
make ethanoic acid
sped up by warming with oxidising agent
eg acidified potassium dichromate
orange to green
chemical properties - carboxylic acids
weak acids
react with metals like normal acids but less vigorously
ethanoic acid
(vinegar)
- weak acid
- reacts with metal to make to make hydrogen and metal salt
salts from carboxylic acids
methanoic > methanoate salt
ethanoic > ethanoate salt
propanoic > propanoate salt
butanoic > butanoate salt
esters reaction
carboxylic acid + alcohols > ester + water
(reversible)
esterification reaction
condensation (water is made)
catalysed by a strong acid eg sulphuric
ester functional group
O
||
O - C
how to bond acid and alcohols (diagram)
remove water and bond together
H O H H
| || | |
H - C - C H - O - C - C - H
| | | |
H O- H H H
naming esters
number of carbons in alcohol + yl eg propyl
number of carbons in acid + anoate eg ethanoate
eg propylethanoate
polymers
very long molecules made by joined repeated smaller molecules
exist in nature or are synthetic
polyethene uses
plastic bags
bottles
PVC used
water pipes
insulation for electricity cables
polypropene uses
crates and ropes
polystyrene
packaging
teflon
non-stick pans
nylon/ terylene uses
clothes
monomer
molecular units that join with similar units to form a polymer
polymerisation
reacting monomer molecules together in a chemical reaction to form polymer chains
two polymerisation types
addition
condensation
addition polymerisation
eg polymerisation of ethene to form poly(ethene)
double bond opens into a single bond and is joined with other monomers
show repeating of the polymer and multiple monomers using ‘n’
addition polymerisation example
H H
| | | |
nC==C > -[-C-C-]-n
| | | |
H H
have to have n to show repeating polymer and multiple monomers
use long - outside square brackets
define addition polymerisation
many monomers bond via rearrangement of bonds without the loss of atoms or molecules
condensation polymerisation
eg polyester
two different monomers join
- double bonds don’t break
- join by eliminating small molecules
- an alcohol with two OH (diol) and a carboxylic acid with two COOH (dioc acid) are the monomers
- makes n(water) also
disposing of polymers
- incineration
- recycling
- landfill
disposing polymers - incineration
- expensive to buy furnace + burn
- releases toxins and pollutants
- pollution affects lung health, noise, traffic
disposing polymers - recycling
- requires energy (expensive)
- melting releases CO2 - requires energy which uses fossil fuels to make
- takes up space - complicated due to lack of education
disposing polymers - landfill
- expensive to dig hole and get line
- releases harmful chemicals and toxic run off
- ugly/ smelly - takes up space that has to be cleared