alcohols Flashcards
what is the functional group of alcohols?
-OH
what happens when you burn ethanol in air?
to form carbon dioxide and water.
what is the oxidation of ethanol?
is when ethanol is oxidised by air with the help of micro-organisms such as bacteria or yeast to form ethanoic acid
explain a way in which ethanol can be oxidised in a lab.
ethanol can be oxidised in a lab by feeling a test tube with potassium dichromate and dilute sulfuric acid and adding a few drops of ethanol to the mixture then the tube is heated in a very hot bath to form a very dilute ethanoic acid.
what is fermentation?
is a process that used industrially to make ethanol.
explain how fermentation works.
fermentation occurs when yeast is added to a sugar solution and left in the warm at about 30 degrees Celsius for several days in the absence if air(anaerobic conditions. then the enzyme in the yeast convert the sugar into ethanol and carbon dioxide.
What occurs when there is air is present in fermentation.
carbon dioxide and water is produced.
what happens when temperature in fermentation is much more than 40 degrees?
The enzymes in the yeast lose their structure and don’t work anymore.
what are the enzymes in the yeast called when they lose their structure?
denatured
what occurs when the temperature is too low?
the reaction takes place slowly.
what is the optimum temperature for fermentation to occur?
30-40 degrees
why is it impossible to make pure alcohol in fermentation?
because yeast is killed by more than 15% of alcohol in the mixture.
how is the alcohol purified?
By fractional distillation because water boils at 100 degrees and alcohol boils at 78 degrees.
how is ethanol made by hydration?
ethanol is made by reaction ethene with steam using the catalyst phosphoric acid.
what temperature should be used for hydration reaction to occur?
300 degrees Celsius.
