Alcohols Flashcards
What is an alcohol?
An organic compound with an -OH group
Draw the structure of the first three alcohols
Methanol, ethanol and propanol
Name a given alcohol, diol or triol
Methanol, Methan-diol, Methan-triol
What are the physical properties of alcohols?
Relatively high mp and bp, miscible with water
Explain the physical properties of alcohols
OH group leads to hydrogen bonding
What are the two methods for production of ethanol?
Fermentation of glucose, hydration of ethene
What are the conditions for the production of ethanol from ethene?
Heat, sulphuric acid catalyst, water
What conditions are necessary for the fermentation of glucose?
Compromise temperature of 35°C, enzymes, sealed vessel
Give two advantages of production of ethanol from glucose
Low tech required, renewable, potentially carbon neutral
Give three disadvantages of production of ethanol from glucose
Slow, Low yield, Significant land use, Has to be distilled, Labour intensive
How is ethanol extracted after fermentation of glucose?
Fractional distillation
Give two advantages of production of ethanol from ethene
Fast reaction, Pure product, Continuous process, Low on manpower, High yield, 100% alcohol
Give three disadvantages of production of ethanol from ethene
High technology, Non-renewable source, Expensive equipment
Write a balanced symbol equation for the complete combustion of a given alcohol
CH4 + 2O2 -> CO2 + 2H2O
What is a dehydration of an alcohol reaction?
One where water is eliminated from an alcohol
What is the product of a dehydration of an alcohol reaction
An alkene
What conditions are necessary for dehydration of an alcohol
Conc. phosphoric/sulphuric acid catalyst, heat and reflux
What is the advantage of dehydrating alcohols to form alkenes?
Alkenes can be used as chemical feedstock without using crude oil
What is an oxidation reaction in organic chemistry?
A reaction where oxygen is added or hydrogen is removed from a compound
What can primary alcohols be oxidized to?
Aldehydes and carboxylic acids
What can secondary alcohols be oxidized to?
Ketones
What can tertiary alcohols be oxidized to?
Nothing
How is oxidation symbolized in an equation?
[O]
What reagent is used for the oxidation of alcohols?
Acidified potassium dichromate
What colour change is observed in the oxidation of alcohols?
Acidified potassium dichromate turns green from orange
Which experimental method is used to convert alcohols to carboxylic acids?
Reflux
Which experimental method is used to convert alcohols to aldehyde
Distillation
Which chemical tests can distinguish between aldehydes and ketones?
Tollens’s reagent or Fehling’s solution
What is observed when Tollens’ reagent is added to aldehydes?
Silver mirror
What is observed when Fehling’s solution is added to aldehydes?
Orange precipitate
