Organic 3 - Chapter 15 , 16 and 25

Question 1

What is the functional group of alcohols

Answer 1

OH
-anol

Question 2

What is the functional group of aldehydes

Answer 2

CO on the end
-al

Question 3

What is the functional group of Ketones

Answer 3

CO in the middle
-one

Question 4

What is the functional group of Carboxylic Acids

Answer 4

COOH
-oic acid

Question 5

What happens when Tertiary alcohols are oxidised

Answer 5

They can’t be oxidised

Question 6

What happens when Secondary alcohols are oxidised

Answer 6

They turn into Ketones

Question 7

What happens when primary alcohols are oxidised

Answer 7

They oxidise to Aldehydes using 1 oxygen

Or Carboxylic acids using 2 oxygens

Question 8

Why cant tertiary alcohols be oxidised

Answer 8

The oxidising agent removes a hydrogen from the -OH group and hydrogen attached to carbon
There is only 1 hydrogen so doesn’t work

Question 9

How is an aldehyde produced from oxidation

Answer 9

Distillation
Alcohol mixed with acidified potassium dichromate solution

Question 10

How is a Carboxylic acid produced by oxidation

Answer 10

Reflux
Mix alcohol and acidified potassium dichromate solution

Question 11

What is reflux

Answer 11

It is when the vapours are prevented from escaping so any aldehydes are returned to be oxidised again

Question 12

What is the test for primary and secondary alcohols

Answer 12

React alcohol with potassium dichromate solution and heat
Turns from orange to green

Question 13

What are tests for aldehydes

Answer 13

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

Question 14

What are the 2 isomers called when there is optical isomerism

Answer 14

Enantionmers

Question 15

What is a racemic mixture

Answer 15

A 50/50 mixture of 2 enantiomers

Question 16

What is required for optical isomerism

Answer 16

When a carbon atom with 4 different groups attached
Known as Chiral

Question 17

What is optical isomerism

Answer 17

When a molecules mirror image is a different molecule

Question 18

How do you tell the difference between optical isomers

Answer 18

They differ on their effect on plane polarised ligh
They rotate the plane of plane polarised light

Question 19

What does it mean that optical isomers are optically active

Answer 19

When the isomers rotate the plane of plane polarised light

Question 20

Which way do the isomers rotate the plane of polarised light

Answer 20

Positive - clockwise
Negative - Anti clockwise

Question 21

What does a carbonyl group have

Answer 21

It consists of a carbon - oxygen double bond

Question 22

What reactions do carbonyl groups do

Answer 22

Reduction
Addition of HCN`

Question 23

What is the reduction of carbonyl groups

Answer 23

Using NaBH4
Lone pair on Negative hydrogen atom attacks carbon and breaks carbon oxygen bond
Oxygen then attacks positive hydrogen atom from solvent

Question 24

What are aldehydes reduced to

Answer 24

Primary alcohols

Question 25

What are ketones reduced to

Answer 25

secondary alcohols

Question 26

What is the addition of HCN reaction with carbonyl groups

Answer 26

They form hydroxynitriles Lone pair on CN- attacks carbon which breaks CO bond, oxygen attacks positive hydrogen ion

Question 27

What are hydroxynitriles

Answer 27

Many are chiral Form racemic mixtures Equal chance of CN- reacting above or below plane

Question 28

What is infra red spectroscopy used for

Answer 28

Used to identify the types of bonds in a molecule

Question 29

How does infra red spectroscopy work

Answer 29

Sample absorbs some frequencies and the frequencies absorbed depend on the different bonds and groups present

Question 30

What is the finger print region

Answer 30

This is the part below 1500 which is unique for every compound and so can be used to identify unknown compounds

Question 31

What is mass spectrometry used for

Answer 31

To find the relative molecular masses of compounds

Question 32

What do the spectrums look like from a Time of Flight mass spectrometer

Answer 32

There are peaks at the main compound and then the fragmentations which have the M/Z as Mr

Question 33

What are carbon environments

Answer 33

They are when a carbon atom is surrounded by atoms and structures which are different to the other carbons in the molecule

Question 34

What do nuclei with an odd mass number possess

Answer 34

Spin

Question 35

What are the types of Nuclear Magnetic resonsance

Answer 35

Carbon 13 Hydrogen 1

Question 36

What is TMS

Answer 36

It provides a reference signal Non-toxic Doesn't react with sample Produces a single peak Low boiling point

Question 37

How does NMR work

Answer 37

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

Question 38

What does the number of signals mean

Answer 38

The number of carbon environments

Question 39

What does the position of the signals mean

Answer 39

Chemical environment of carbons

Question 40

What is the test for alkenes

Answer 40

Bromine water decolourises

Question 41

What is the test for Haloalkanes

Answer 41

Warm with NaOH cool and add nitric acid Then add silver nitrate White precipitate (chloroalkane) Cream precipitate (bromoalkane) Yellow Precipitate (iodoalkane)

Question 42

What is the test for Primary, secondary alcohols and aldehydes

Answer 42

Acidified potassium dichromate Turns from orange to green

Question 43

What is the test for aldehydes only

Answer 43

Fehlings solution Forms brick red precipitate Tollens Reagent Forms a silver mirror

Question 44

What is the test for carboxylic acids

Answer 44

Sodium carbonate Fizzing