alcohols Flashcards
what are alcohols?
organic molecules containing an OH- functional group
what does the start of the name show?
the number of carbon atoms it has
what does the end of the name show?
-ol to show its an alcohol `
what are the 3 main categories of formula used to represent alcohols on paper?
molecular formula
structural formula
displayed formula
what does the molecular formula show?
just each element, only once
doesn’t show the structure of the molecule at all
what does the displayed formula show?
each atom and every bond drawn out
perfectly shows the structure of the molecule
what are the 2 methods to make ethanol?
hydration of ethene
fermentation of glucose
in hydration of ethene, what is ethene mixed with?
steam
what are the conditions for the hydration of ethene?
300 degrees celsius
65 atm pressure
phosphoric acid (H3PO4) catalyst
what raw material provides the ethene in the hydration of ethene?
crude oil
what are the advantages of the hydration of ethene?
makes pure ethanol
can run continously
what are the disadvantages of the hydration of ethene?
conditions require lots of energy
non- renewable raw material used
what happens in the fermentation of glucose?
glucose is fermented microbiologically under the following conditions:
yeast- provides enzymes
30 degrees celsius- enzymes optimum temperatures
anaerobic- prevents oxidation
what raw material in the fermentation of glucose provides the glucose?
sugar cane
what are the advantages of the fermentation of glucose?
renewable raw material used
conditions not energy intensive
what are the disadvantages of the fermentation of glucose?
makes impure ethanol
must be done in individual batches
what are the 3 ways ethanol can be oxidised?
combustion
microbial oxidation
chemical oxidation
why does ethanol combust completely?
because of the oxygen atom in the OH- group
what flame does the combustion of ethanol have?
a non-luminous, blue flame
formula for combustion of ethanol?
C2H5OH + 3O2 -> 2CO2 + 2H2O
what do micro-organisms use to oxidise ethanol into ethanoic acid?
the oxygen in the air
under what conditions can microbial oxidation happen?
aerobically- if the microorganism is growing in the presence of air
what does the (O) show?
the microbial use of oxygen in an equation
what is the equation for microbial oxidation?
C2H5OH + 2(O) -> CH3COOH + H2O
what do we use when we want to deliberately oxidise ethanol in the lab?
we heat it with a mixture of:
potassium dichromate (VI) (K2Cr2O7)
dilute sulphuric acid (H2SO4)
what does chemical oxidation form?
ethanoic acid
what is the formula for chemical oxidation?
C2H5OH + 2(O) -> CH3COOH + H2O
what are the orange dichromate (VI) ions turned into?
green chromium (III) ions
