Alcohols
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What is the general formula for an alcohol?
CnH2n+1OH
What functional group do alcohols contain?
Hydroxyl group (-OH)
What suffix is used when naming alcohols?
-ol.
How is the position of the OH group shown in longer alcohols?
A number before the -ol.
How are multiple OH groups shown in a name?
Prefixes di- tri- tetra-
When is the prefix hydroxy used?
When the alcohol is not the main functional group.
What is a primary alcohol?
The C with the OH attached has 1 alkyl group attached.
What is a secondary alcohol?
The C with the OH attached has 2 alkyl groups attached.
What is a tertiary alcohol?
The C with the OH attached has 3 alkyl groups attached.
What is the bond angle around Carbon in alcohols?
109.5 (tetrahedral)
What is the H-O-C bond angle?
104.5
Why is the H-O-C bond angle reduced?
Lone pairs repel more than bonding pairs.
Why do alcohols have higher boiling points than alkanes?
Hydrogen bonding between molecules.
Why do small alcohols dissolve in water?
They form hydrogen bonds with water.
Why do longer alcohols dissolve better in non-polar solvents?
Hydrogen bonding is only about the oH group, not the alkyl chain.
What is the equation for hydration of ethene?
CH2=CH2 + H2O(g) –> CH3CH2OH
What are the conditions for hydration of ethene?
Concentrated H3PO4 catalyst, steam, 450 degrees, 50-100 atm.
What type of mechanism is hydration?
Electrophilic attack
What is the equation for fermentation?
C6H12O6 –> 2CH3CH2OH +2CO2
What are the conditions for fermentation?
Yeast enzymes, around 35 degrees, no oxygen
Why must no oxygen be present?
Ethanol may oxidise to ethanoic acid.
Why is 35 degrees used in fermentation?
Too cold= slow rate; too hot= enzymes denature
Why is distillation needed after fermentation?
Ethanol has a lower boiling point than water.
Give one advantage of hydration.
Fast rate of reaction.