organic chemistry (75-78, 80) (paper 2) Flashcards
what is the functional group for an alcohol
OH - oxygen hydrogen
what is the functional group for carboxylic acids
carbon double bonded to an oxygen and the carbon bonded to an OH
what is the functional group for esters
a carbon double bonded to an oxygen and the carbon bonded to a O
what is the prefix for alcohol
-ol
what is the prefix for carboxylic acids
-oic acid
what is the prefix for esters
-yl -anoate
what is the general formula for alcohols
CnH2n+1OH
which is bonded to the carbon the O or the H
the O
what can alcohols be oxidised to form
carboxylic acids
what is the oxidising agent for alcohols -> carboxylic acids
potassium dichromate solution with dilute sulfric acid with some heat
how else are carboxilic acids formed from alcohols
microbial oxidation = microorganisms
what is distilation
evapouration followed by condensation
when is purifying ethanol used
- making alcoholic drinks
- ethanol for cars
- alternative in chemical industry
what are the two methods to make ethanol
- fermentation
- direct hydration
what are the reagents and conditons for fermentation
- sugars from plants
- 30degrees
- anerobic conditions
- catalyst = yeast
why does fermentation take place in anaerobic conditions
because it will oxidise the ethanol to ethanoic acid
what is the equation for fermentation
C6H12O6 -> 2C2H5OH + 2CO2
glucose -> ehtanol + carbon dioxide
what are the advantages and disadvantages of fermentation
+renewable resource
+low tech equipment
+only small temps needed
-waste product CO2
-not concerntrated enough = must be distilled
-slow
what are the reagents and condition for direct hydration
- ethene cracked from crude oil
- water as steam
- catalyst = phosphoric acid
- 300degrees celcius
- pressure 60-70atmospheres
what is the catalyst for fermentation
yeast
what is the catalyst for direct hydration
phosphoric acid
what is the equation for direct hydration
C2H4 + H2O -> C2H8OH
ethene + water -> ethanol
what are the advantages and disadvantages of direct hydration for ethanol production
+fast & more efficient
+cheap
-non-renewable method
-lots of energy required for temperatures
what is ethanol oxidised to form
ethanoic acid
how is ethanoic acid formed
- potassium dichromate solution with sulfuric acid
- colour change orange - green
do carboxylic acids react like all other acids
yes
what does a metal + acid form
salt + hydrogen
what does an alkali/base + acid form
salt + water
what does a carbonate + acid form
salt + carbon dioxide + water
what is the functional group of an ester
-COO-
what is the functional group of a carboxylic acid
-COOH
how are esters formed
alcohol + carboxylic acid
what is the waste product when esters are formed
water
what is the catalyst usually used for the formation of esters
sulfuric acid and heat
how can you make esters in the lab
- add some concertrated sulfuric acid in boiling tube with pipette
- add ethanoic acid
- add equal amount of ethanol
- heat using a bunsern burner till boiling
- after one min allow to cool
- add to sodium carbonate and ester will form
what are esters used for
perfumes and flavourings
what are the rules for when esters are being produced when writing the equations
- carboxylic acid loses ‘OH’
- alcohol loses ‘H’
- join where lost
what must happen for a monomer to become a polymer
the double bond is broken
how are polyesters formed
condensation polymerisation
what is condensation polymerisation
when dicarboxylic acid monomers and diol monomers react together
What charge do carboxylic acids have when reacting with a metal or any other element
1-
What is the reversible equation for a carboxylic acid donating H* ions in a solution (eg. Ethanoic acid)
CH3COOH -> (H2O) -> CH3COO- + H+
What is the colour change in the oxidation of ethanoic acid by using potassium dichromate solution with sulfuric acid
Changes from orange to green
define fermentation
fermentation is the anaerobic respiration of sugars by yeast cells to produce ethanol and carbon dioxide
