3.5 Alchols Flashcards
(11 cards)
What are the conditions needed for fermentation to occur?
1 mole of glucose into two moles of ethanol and 2 moles of carbon dioxide
Done at 30-40 degrees (so enzymes will not denature or it won’t be too slow)
No oxygen as it is anaerobic
The solution can be filtered and distilled to obtain pure ethanol.
define biofuel
A fuel that can be replaced faster then it is being used up
Why would biofuel/ fermentation not be considered 100% carbon neutral?
- energy required for machinery
- energy to maintain the temp for fermentation
- energy to distill the ethanol
What is the mechanism is used for an alkene to react with steam to create an alcohol?
Electrophilic addition
reaction of ethene to ethanol
CH4 + H20 = ch3ch2OH
why do aldehydes and ketones have a lower boiling point then the alcohol they originate from?
aldehydes and ketones have only dipole to dipole whereas alcohols have hydrogen bonding which is stronger
why do reflux reaction conditions require an excess of oxidising reagent?
Firstly an aldehyde is formed and will evaporate
the vapours reach the condenser, condense and drip back into the reaction mixture
Ensure that the aldehyde can be fully oxidised to the carboxylic acid
reflux can be carried out for an extended period time to ensure a complete reaction
how do we separate carboxylic acid after reflux reactions
the carboxylic acid will be obtained through distillation
what are the conditions for making carboxylic acid and aldehydes through reflux reactions?
Excess oxidising reagent
vertical condenser
for aldehydes
distillation and stoichiometric amounts of oxidising reagent
results for Fehling’s test?
aldehyde- brick red precipitate
ketone- remains blue precipitation
Results for Tollens reagent?
Ketone- colourless
aldehyde - a silver mirror
