Organic Chemistry - SPEC Flashcards
how are polymers made and what is this process called
made by linking together large numbers of monomers
addition polymerisation
how is each monomer connected within a polymer
with covalent bonds
what conditions do polymerisation reactions need
- high pressures
- the use of a catalyst
what are synthetic polymers
those that are manufactured such as polystyrene and nylon
how to change a polymer into a polymer (for a drawing)
remove the two extending single bonds and create a double bond instead
why are polymers a problem for the environment
they have strong C-C bonds which makes them unreactive and chemically inert so they don’t easily biodegrade
what are the options for disposing of polymers
- landfill
- incineration
- recycling
why is landfill not a good option for disposing of polymers
this takes up valuable land because site quickly fill up
why is incineration not a good option for disposing of unwanted polymers
- they release the greenhouse gas carbon dioxide
- polymers that contain chlorine release hydrogen chloride gas when burned
- if incinerated with incomplete combustion then carbon monoxide is produced
what are the problems with recycling unwanted polymers
different polymers must be separated from each other which is a difficult and expensive process
when are condensation polymers formed
when two different monomers are linked together with the removal of a small molecule - usually water
what is a key difference between addition polymerisation and condensation polymerisation
addition polymerisation forms the polymer molecule only
WHEREAS
condensation polymerisation forms the polymer molecule (polyester) and one water molecule per link
WHAT ARE THE REACTANTS AND PRODUCTS OF CONDENSATION POLYMERISATION
REACTANTS = dicarboxylic acid, diol
products = polyester, water
what is a dicarboxylic acid monomer
a carboxylic acid with a -COOH group at BOTH ends
what is a diol
an alcohol with an -OH group on BOTH ends
how do the diols and dicarboxylic acids react with each other to form a polymer
Each -COOH group reacts with another -OH group on another monomer
this creates a long chain of alternating monomers
how is water formed in condensation polymerisation
For every ester linkage formed, one molecule of water is formed from the combination of a -H and an -OH group
give one example of a dicarboxylic acid
ethanedioic acid
-dioic
give one example of a diol
ethanediol
- diol
what do each of the atoms come from that form water in condensation polymerisation
The OH comes from the -COOH groups of the dicarboxylic acid
The H comes from the -OH groups of the diol
what is hydrolysis
adding water to the polyester which allows it to break back down into its monomers, reversing condensation polymerisation
how to deduce the monomers from the polyester
- then the OH atoms are added back onto the C=O
and H atoms added onto the oxygen atoms on the other structure
what are biopolyesters
a specific type of polymer that are synthesised from sugars and plant oils using microorganisms
they are able to biodegrade naturally in the environment
how are esters made and what is the process called
made when alcohols and carboxylic acids react
esterification
what is the functional group of esters
R - COO - R
where the R symbolises whatever
what are esters used for
food flavourings
perfumes
how to name an ester
- The first part of the name indicates the length of the carbon chain in the alcohol, and it ends with the letters ‘- yl’
- The second part of the name indicates the length of the carbon chain in the carboxylic acid, and it ends with the letters ‘- oate’
- e.g. the ester formed from pentanol and butanoic acid is called pentyl butanoate
how is ethyl ethanoate produced
when ethanol and ethanoic acid react in the presence of an acid catalyst
what is one characteristic of esters
they are volatile
what is the general formula for carboxylic acids
Cn H2n+1 COOH
how do carboxylic acid react with metals of carbonates and why
They react with metals to form a salt and hydrogen and with carbonates to form a salt, water and carbon dioxide gas
because they behave like other acids
they also take part in neutralisation reactions to produce salt and water
how to name the salts formed by the reaction of carboxylic acids
they all end -anoate
So methanoic acid forms a salt called methanoate, ethanoic a salt called ethanoate etc
what is formed in the reaction between ethanoic acid and magnesium and why
magnesium ethanoate and hydrogen
carboxylic acid + metal -> metal salt + hydrogen
what would be formed in the reaction between potassium hydroxide and propanoic acid
potassium propanoate and water
(carboxylic) acid + alkali -> salt + water
how do the atoms change when carboxylic acids react to form salts
they lose the last hydrogen and replace it with the metal
what is an alcohol in general terms
a colourless liquid that dissolves in water to form neutral solutions
what is a use for the first four alcohols
used as fuels
what are methanol and ethanol commonly used for and why
SOLVENTS
they can dissolve many substances that water cannot such as fats and oils, ASWELL as dissolving most of the things that water can
what are the first four alcohols
methanol ethanol propanol butanol
how do you name alcohols
remove the final e and replace it with ol
what are the three methods of oxidising ethanol
- combustion
- microbial oxidation
- heating with potassium dichromate(VI) in dilute sulfuric acid
what is microbial oxidation
the reaction with oxygen in the air
bacteria in the air (acetobacter) use atmospheric oxygen from the air (so this reaction can only occur aerobically)
what happens to alcohols when they undergo combustion
they form carbon dioxide and water
what colour does ethanol burn with
an almost invisible blue flame
what is the formula for when ethanol undergoes microbial oxidation
ethanol + oxygen -> ethanoic acid + water
why do wines end up tasting acidic when left open for too long
microbial oxidation of the ethanol - the bacteria form ethanoic acid, the same acid used in vinegar
what happens when an alcohol undergoes oxidation
it forms a carboxylic acid
what is the formula for when ethanol is heated with acidified potassium dichromate solution
ethanol + [O] -> ethanoic aicd + water
during the reaction when ethanol is heated with acidified potassium dichromate solution, what colour change is there
and why
the potassium dichromate turns from orange to green
dichromte ions turn into chromium ions
why does ethanol tend to combust completely when oxidising it through combustion
because of the oxygen atom in the OH group
during the reaction when ethanol is heated with acidified potassium dichromate solution, why do we place a condenser above the reaction flask
to prevent the volatile liquids from evaporating and escaping
Crude oil fractions
Really gay kids don’t fuck boys
Refinery gases
Gasoline
Kerosene
Diesel
Fuel oil
Bitumen
what is esterification
when alcohols and carboxylic acids react to make esters
uses of esters
perfumes and food colourings
structure of ethyl ethanoate
how to name esters
eg the ester formed from pentanol and butanoic acid
PENTyl BUTANoate
