| what is a primary alcohol | an alcohol in which the -OH group is attached to the end of the carbon chain |
| what is a secondary alcohol | an alcohol in which the carbon attached to the -OH group is attached to two other carbon atoms |
| what is a tertiary alcohol | an alcohol in which the carbon atom attached to the -OH group is attached to three other carbons |
| what types of alcohols can be oxidised | primary and secondary alcohols |
| can tertiary alcohols undergo oxidation readily? | no |
| what oxidising agents are used to oxidise primary and secondary alcohols | acidified potassium dichromate
hot copper(II) oxide |
| what the colour change when primary alcohols are oxidised using hot copper(II) oxide | black copper(II) oxide forms a brown solid |
| what is formed when primary alcohols are oxidised | aldehydes |
| what is formed when secondary alcohols are oxidised | ketones |
| what is the functional group of aldehydes and ketones | carbonyl group (C=O) |
| what are many flavour an aroma molecules known as | aldehydes |
| where is the carbonyl group found in aldehydes | at the end of the carbon chain, with a hydrogen atom attached to it |
| where is the carbonyl group found in ketones | joined to two other carbon atoms, with no hydrogen atom attached to it |
| do you need to indicate the number for the functional group when naming an aldehyde | no
the carbonyl group is always at the end of the carbon chain |
| do you need to specify the number of the carbonyl group when naming ketones | yes |
| what substances can be used to distinguish between aldehydes and ketones | oxidising agents |
| can aldehydes be oxidised | yes |
| can ketones be oxidised | no |
| what are the oxidising agents used for oxidising aldehydes | Fehling's solution
Tollen's reagent
acidified potassium dichromate |
| explain the colour change observed when using acidified potassium dichromate solution to oxidise aldehydes | orange to green
as dichromate ions/Cr2O7 2- (aq) is reduced to chromium ions/Cr3+(aq) |
| explain the colour change observed when fehling's solution is used to oxidise aldehydes | Blue to orange/red
as copper 2+ ions/cu2+(aq) are reduced to copper 2 oxide solid/Cu2O(s) |
| explain the colour change observed when tollen's reagent is used to oxidise aldehydes | colourless to silver
as silver ions/Ag+(aq) is reduced to silver solid/Ag(s) |
| what is formed when aldehydes are oxidised | carboxylic acids |
| what does it mean when the oxygen to hydrogen ratio of carbon compounds has increased | oxidation has taken place |
| what does it mean when the oxygen to hydrogen ratio of carbon compounds has decreased | reduction has taken place |
| are carbonyl, carboxyl, amine and amide groups polar or non polar | polar |
| what effect does oxygen in the air have on food | it can cause the oxidation of the food |
| what effect does the oxidation of edible oil have on food | gives food a rancid flavour |
| how can the oxidation of food be prevented | the addition of an antioxidant to the food |
| what are antioxidants | reducing agents
they will readily undergo oxidation to prevent food from becoming oxidised |
