Organic 3 - Chapter 15 , 16 and 25 Flashcards
What is the functional group of alcohols
OH
-anol
What is the functional group of aldehydes
CO on the end
-al
What is the functional group of Ketones
CO in the middle
-one
What is the functional group of Carboxylic Acids
COOH
-oic acid
What happens when Tertiary alcohols are oxidised
They can’t be oxidised
What happens when Secondary alcohols are oxidised
They turn into Ketones
What happens when primary alcohols are oxidised
They oxidise to Aldehydes using 1 oxygen
Or Carboxylic acids using 2 oxygens
Why cant tertiary alcohols be oxidised
The oxidising agent removes a hydrogen from the -OH group and hydrogen attached to carbon
There is only 1 hydrogen so doesn’t work
How is an aldehyde produced from oxidation
Distillation
Alcohol mixed with acidified potassium dichromate solution
How is a Carboxylic acid produced by oxidation
Reflux
Mix alcohol and acidified potassium dichromate solution
What is reflux
It is when the vapours are prevented from escaping so any aldehydes are returned to be oxidised again
What is the test for primary and secondary alcohols
React alcohol with potassium dichromate solution and heat
Turns from orange to green
What are tests for aldehydes
Fehlings solution and heat - Turned brick red
Tollens reagent - Silver nitrate and sodium hydroxide with ammonia solution and heated - Silver mirror
Acidified Potassium Dichromate Solution and heat - changed green
What are the 2 isomers called when there is optical isomerism
Enantionmers
What is a racemic mixture
A 50/50 mixture of 2 enantiomers
What is required for optical isomerism
When a carbon atom with 4 different groups attached
Known as Chiral
What is optical isomerism
When a molecules mirror image is a different molecule
How do you tell the difference between optical isomers
They differ on their effect on plane polarised ligh
They rotate the plane of plane polarised light
What does it mean that optical isomers are optically active
When the isomers rotate the plane of plane polarised light
Which way do the isomers rotate the plane of polarised light
Positive - clockwise
Negative - Anti clockwise
What does a carbonyl group have
It consists of a carbon - oxygen double bond
What reactions do carbonyl groups do
Reduction
Addition of HCN`
What is the reduction of carbonyl groups
Using NaBH4
Lone pair on Negative hydrogen atom attacks carbon and breaks carbon oxygen bond
Oxygen then attacks positive hydrogen atom from solvent
What are aldehydes reduced to
Primary alcohols
What are ketones reduced to
secondary alcohols
What is the addition of HCN reaction with carbonyl groups
They form hydroxynitriles
Lone pair on CN- attacks carbon which breaks CO bond, oxygen attacks positive hydrogen ion
What are hydroxynitriles
Many are chiral
Form racemic mixtures
Equal chance of CN- reacting above or below plane
What is infra red spectroscopy used for
Used to identify the types of bonds in a molecule
How does infra red spectroscopy work
Sample absorbs some frequencies and the frequencies absorbed depend on the different bonds and groups present
What is the finger print region
This is the part below 1500 which is unique for every compound and so can be used to identify unknown compounds
What is mass spectrometry used for
To find the relative molecular masses of compounds
What do the spectrums look like from a Time of Flight mass spectrometer
There are peaks at the main compound and then the fragmentations which have the M/Z as Mr
What are carbon environments
They are when a carbon atom is surrounded by atoms and structures which are different to the other carbons in the molecule
What do nuclei with an odd mass number possess
Spin
What are the types of Nuclear Magnetic resonsance
Carbon 13
Hydrogen 1
What is TMS
It provides a reference signal
Non-toxic
Doesn’t react with sample
Produces a single peak
Low boiling point
How does NMR work
The sample is dissolved ina solvent like CCl4 or CBCl3
TMS is then added
The sample is spun in a magnetic field and radiation is applied
What does the number of signals mean
The number of carbon environments
What does the position of the signals mean
Chemical environment of carbons
What is the test for alkenes
Bromine water
decolourises
What is the test for Haloalkanes
Warm with NaOH
cool and add nitric acid
Then add silver nitrate
White precipitate (chloroalkane)
Cream precipitate (bromoalkane)
Yellow Precipitate (iodoalkane)
What is the test for Primary, secondary alcohols and aldehydes
Acidified potassium dichromate
Turns from orange to green
What is the test for aldehydes only
Fehlings solution
Forms brick red precipitate
Tollens Reagent
Forms a silver mirror
What is the test for carboxylic acids
Sodium carbonate
Fizzing
