Chemistry - Unit 2, Module 2 (Alcohols, Halogenoalkanes and analysis)

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  • Created by: Lucy
  • Created on: 02-04-13 15:31
What is a general equation for the combustion of alcohols?
C2H5OH(l) + 3O2(g) --> 2CO2(g) + 3H2O(l)
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How are primary and secondary alcohols oxidised?
Using an oxidising agent
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What is a suitable oxidising agent?
-A suitable oxidising agent is a solution containing acidified dichromate ions, H+/ Cr2O7 (2-)
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How can you make this oxidising mixture?
This oxidising mixture can be made from potassium dichromate, K2Cr2O7, and sulfuric acid, H2SO4. During the reaction, the acidified pottasium dichromate changes colour from orange to green.
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What do you get when you oxidise a primary alcohol?
An aldehyde. Functional group: -CHO
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What happens when you oxidise a primary alcohol whilst applying a high heat (i.e. Under reflux)?
The alcohol will be completely oxidised, passing through the aldehyde stage, to form a carboxylic acid. Functional group: -COOH
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How can you ensure you get an aldehyde when oxidising a primary alcohol?
You have to distil off the aldehyde from the reaction mixture as it is formed. This prevents the aldehyde from being oxidised futher to form a caboxylic acid.
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Define Relux.
Reflux is the continual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling dry.
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What happens when you oxidise secondary alcohols?
Secondary alcohols are oxidise by acidified dichromate ions to produce ketones. Functional group -C-CO-C-
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What happens when you oxidise tertiary alcohols?
Tertiary alcohols are resistant to oxidation and so cannot be oxidised.
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Why do alcohols dissolve in water?
Alcohols dissolve in water because hydrogen bonds form between the polar -O-H groups of the alcohol and water molecues.
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Other cards in this set

Card 2

Front

How are primary and secondary alcohols oxidised?

Back

Using an oxidising agent

Card 3

Front

What is a suitable oxidising agent?

Back

Preview of the front of card 3

Card 4

Front

How can you make this oxidising mixture?

Back

Preview of the front of card 4

Card 5

Front

What do you get when you oxidise a primary alcohol?

Back

Preview of the front of card 5
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Comments

Stephen

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Really good! Thanks! :-)

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