Alcohols Flashcards
(30 cards)
What are the physical properties of alcohols ?
- relatively high melting and boiling points
- soluble in water
- low volatility
Why do alcohols have high melting and boiling points ?
- they have hydrogen bonds, which take more energy to overcome
Why are alcohols soluble in water ?
alcohols form hydrogen bonds with water molecules
What happens to the solubility of alcohols as the chain length increases ?
as chain length increases, the influence of the -OH becomes smaller, and so solubility decreases
What are the products of complete combustion ?
carbon dioxide and water
What is the only reaction we can write using molecular formulae ?
combustion reactions
What are the products of incomplete combustion ?
What is a primary alcohol ?
an alcohol where the C bonded to the -OH is also bonded to 1 other carbon
What is a secondary alcohol ?
an alcohol where the C bonded to the -OH is also bonded to 2 other carbons
What is a tertiary alcohol ?
an alcohol where the C bonded to the -OH is also bonded to 3 other carbons
What are the reagents for the oxidation of an alcohol ?
K2Cr2O7 and H2SO4
acidified potassium chromate
What are the observations during the oxidation of an alcohol ?
acidified potassium chromate changes colour from orange to green
What labels are needed for a diagram of distillation ?
- heat
- flask
- still head
- thermometer
- water in
- water out
- condenser
- beaker
What two conditions can oxidation of an alcohol be done under ?
- heat under distillation
- heat under reflux
What is produced when a primary alcohol is oxidised under distillation ?
an aldehyde and water
What is produced when a primary alcohol is oxidised under reflux ?
a carboxylic acid and water
What labels are needed for a diagram of reflux ?
- heat
- flask
- condenser
- water in
- water out
What condition are secondary alcohols oxidised under ?
reflux
What is produced during the oxidisation of secondary alcohols ?
a ketone and water
Why are tertiary alcohols not oxidised under reflux or distillation ?
there isn’t a hydrogen bonded to the C that the -OH is attached to, so a water molecule isn’t produced
What is the functional group of an aldehyde ?
O=C-H
What is the functional group of a carboxylic acid ?
O=C-OH
What is the reagent of the test for a carboxylic acid ?
NaCO3 (metal carbonate)
What is the observation of the test for a carboxylic acid ?
bubbles seen as CO2 is produced
