Alcohols and Carboxylic acids Flashcards
Recall the formulae of molecules of the alcohols, methanol, ethanol,
propanol (propan-1-ol only) and butanol (butan-1-ol only), and draw the
structures of these molecules, showing all covalent bonds
● Alcohols contain the functional group –OH
● The first 4 members of the series are methanol, ethanol, propanol and butanol
methanol CH 3 OH
ethanol CH 3 CH 2 OH
propanol CH 3 CH 2 CH 2 OH
butanol CH 3 CH 2 CH 2 CH 2 OH
Investigate the temperature rise
produced in a known mass of water by the combustion of
the alcohols ethanol, propanol, butanol, and pentanol
● in this experiment, you should find that the temperature is raised more as the
chain length of the alcohols increases, because the combustion of longer chain
alcohols releases more energy
Recall the formulae of molecules of the carboxylic acids, methanoic,
ethanoic, propanoic and butanoic acids, and draw the structures of these
molecules, showing all covalent bonds
● Ethanoic acid is a member of the carboxylic acids, they have
the functional group –COOH.
● First four members are: methanoic acid, ethanoic acid,
propanoic acid and butanoic acid
methanoic acid CHOOH
ethanoic acid CH 3 COOH
propanoic acid CH 3 CH 2 COOH
butanoic acid CH 3 CH 2 CH 2 COOH
Recall that ethanol can be oxidized to produce _______ _____ and
extend this to other alcohols (reagents not required)
● Ethanol can be oxidised to form ethanoic acid.
● any alcohol can be oxidised to produce a carboxylic acid (e.g. propanol →
propanoic acid)
Recall members of a given homologous series have
similar reactions because their molecules contain the same functional group and use this to predict the products of other members of these series
Describe the production of ethanol by fermentation of carbohydrates
in aqueous solution, using yeast to provide enzymes
● Ethanol can be produced by fermentation with yeast, using renewable sources.
● it is produced from carbohydrates (can be sugars from fruit or starch)
● mixture must be kept warm and under anaerobic conditions (warm- so reaction is fast enough but yeast doesn’t denature. Anaerobic- only carbon dioxide and
water would be produced if not) glucose → ethanol + carbon dioxide
C6 H12 O6 → 2C2 H5 OH + 2CO2
Explain how to obtain a concentrated solution of ethanol by fractional
distillation of the fermentation mixture
● Ethanol concentration is about 15% from fermentation, ethanol is separated
from the reaction mixture using fractional distillation
○ water and ethanol solution are heated
○ ethanol evaporates first (has a lower boiling point than water), cools,
then condenses
○ water left evaporates, cools, then condenses
