3.3.6 - Organic Analysis Flashcards
1º and 2º alcohols are identified using…
acidified potassium dichromate
Positive test for 1º and 2º alcohols
orange to green
Aldehydes are identified using…
tollen’s reagent and fehling’s solution
Positive test for aldehydes with tollens reagent
Silver mirror forms
Positive test for aldehydes with fehling’s solution
blue solution to a brick red precipitate
Unsaturated hydrocarbons are identified using…
Bromine water
Positive test for unsaturated hydrocarbons
orange-brown to colourless is C-C double bond is present
Carboxylic acids are identified by…
reacting them with sodium carbonate, and then bubbling the CO2 through limewater
Positive test for carboxylic acids
Limewater turns cloudy
High resolution mass spectrometry
More sensitive form of mass spectrometry which allows the Mr to be determined to several decimal places. Precise atomic masses are always given and can be used to calculate the molecular formula of the compound being tested
Infrared spectrometry
Uses IR radiation to determine the functional groups present in organic compounds. The IR radiation is passed through a sample where different bonds absorb radiation in different amounts. These varying amounts of absorbance are measured and recorded allowing certain bonds and therefore functional groups to be identified
A spectrum is produced from…
The measurements which has characteristic curves for the different functional groups
Fingerprint region
Contains tiny differences from species to species which act as a molecules ‘fingerprint’, allowing it to be identified
IR absorption also occurs in…
The atmosphere with molecules such as ozone. This causes heat to be trapped within the Earth’s atmosphere
Global warming
When chemicals such as CFCs are released into the atmosphere from human activity, heat is trapped at an advanced rate, leading to global warming
