Stage 2 Chemistry, Unit 3- Organic and Biological Chemistry

3.1-3.10

Primary Alcohols

have their Hydroxyl groups at the end of a chain(terminal (are only connected to one carbon

Secondary Alcohols

have their hydroxyl groups within the chain (are connected to two carbons)

Tertiary Alcohols

have their hydroxyl group within a chain which a substituent is branching (connected to three carbons)

Alcohols oxidise to lose

Two hydrogens, allowing for a Carbon-oxygen double bond to be formed

A primary Alcohol is oxidised (in acidic conditions) into a

Aldehyde

A secondary Alcohol is oxidised (in acidic conditions) into a

Ketone

An Aldehyde can be oxidised further in acidic conditions to form

Carboxylic acid

An Aldehyde can be further oxidised in alkaline conditions to form

carboxyl ion

If an acidified potassium dichromate solution turns from orange to green with an alcohol,

it is a primary or secondary Alcohol (as it can be oxidised)

if a silver Mirror forms when tollen’s reagent and silver is added to this Alcohol

It is an Aldehyde

If nothing happens within the acidified potassium dichromate

The Alcohol is tertiary

If nothing happens when Tollen’s reagent is added to the Alcohol

it is a Ketone

How does Tollen’s reagent work?

Tollen’s reagent allows for the alkaline oxidation of Aldehydes, forming carboxylate ions. The aldehyde’s ions are donated to the Silver ions, making them solid

in any structure lines linking to O or OH

do not indicate new carbons

Monosaccharides

are individual sugar molecules, which are monomers for complex carbohydrates

Examples of Monosaccharides

Glucose, Fructose

Disaccharides

Two monosaccharide sugars bonded together with covalent bonds

Example of Disaccharides

Lactose, Sucrose, Maltose

disaccharides are formed through

condensation( which releases water to bond the two sugars together)

carbohydrates are

classified as polyhydroxyl aldehydes or polyhydroxyl ketones

what are polyhydroxy Aldehydes

Aldehydes with multiple hydroxyl function groups

What are polyhydroxy Ketones

Ketones with multiple hydroxyl function groups

in aqueous equilibrium, monosaccharides exist in

cyclical and chain form

At equilibrium, monosaccharide’s

cyclical structure is heavily favoured (only 0.02% is chain form )

Suffix for Alcohols

-ol

Suffix for Aldehydes

___-N-al

suffix for Ketones

___-N-one

Suffix for Carboxylic acids

-ioc acid

Suffix for double carboxyl group carboxylic acids

alkane name+dioic acid

Carboxylic acids have

a high melting/boiling point, and good solubility

Carboxylic acids are miscible from

Methanoic to butanoic

When Carboxylic acid reacts with metals

it is not always soluble (+1 charges are)

When Benzene (aromatic) is used as a function group, it is called

phenyl

How are Carbohydrates indentified?

As Polyhydroxy-Aldehydes or Polyhydrox-Ketones

(or substances that will form these during hydrolysis)

What is the reaction name when two monosaccharides join to form a disaccharide?

Condensation

What is the name of the reaction when a disaccharide breaks into two monosaccharides?

hydrolysis

Acidified Potassium Dichromate changes colour from Orange to Green by

converting the primary or secondary Alcohol into either a Aldehyde or a Ketone

What are Esters formed from?

A condensation reaction between Carboxylic acid (ROOH) and an alcohol (ROH)

Naming esters

Alkyl group is named first (-yl) then carbonic acid group (-oate)

Esters have

a lower boiling point than their carboxylic acid and alcohol counterparts

Alcohol functional group

-OH (Hydroxyl

Ketone functional group

C=O ( non terminal carbonyl

What is the functional group of an amine

-NH₂

Primary amines are

covalently bonded to one carbon and have two hydrogens

Secondary amines are

covalently bonded to two carbons and have one hydrogen

Amines can

accept protons,forming a covalent bond with the proton with nitrogen’s lone pair of electrons

What is the name of amines after they have accepted a proton?

protonated amine

What is the ester functional group?

COOC

how are poly esters made?

between condensation between a diol and a dicarboxylic acid

What is the name of one of the Esterification reactions

Fischer esterification

Esterification requires an

acid catalyst of concentrated sulphuric acid

Esterification is

a reversible reaction, so it reaches equilibrium

Esterification’s Kc value is

<1, so favours the reverse

How is Le Châtlier’s principle and collision theory used to optimise esterification

an excess of alcohol is use to shift the equilibrium to the right, favouring the products, while increasing the temperature increases the rate that condensation occurs

Esters can only interact between eachother with

dipole-dipole bonds

Ester’s boiling point

are much lower than carboxylic acids or alcohols

Small esters are

soluable in water

The result of ester Hydrolysis is

dependent on the pH

Acidic hydrolysis

requires a strong acid catalyst, and forms the orginal carboxylic acid and alcohol(reversible

Alkaline Hydrolysis

Requires a strong base catalyst, the alcohol and a carboxylate ion are formed (not reversible)

How are Amides formed?

Amides are formed between a condesation reaction between an amine and a carboxylic acid.

What is the amide functional group?

C=O-N(H)-R

Naming amides is not required, although

they are named by naming N, the alkyl group from N and the amine, changing the suffix to amide

Primary amides

have one carbon directly attached to the Nitrogen

Secondary Amides have

two carbon bonded to the nitrogen

Tertiary amides have

3 carbons bonded to the nitrogen

the amide functional group is

polar, and it can form hydrogen bonds with water, meaning with small chain lengths it is soluable

Polyamides are formed through

a condensation reaction between diamines and dicarboxylic acids

Acid Hydrolysis of Amides

requires an acid catalyst and hot water under reflux

what products are formed from acid hydrolysis

the original Carboxylic acid, and a protonated amine (reversible

Alkaline Hydrolysis

requires a strong base (usually NaOH) and is done under reflux

products from Alkaline hydrolysis

the reaction forms a carboxylate anion and an amine. The carboxylate anion forms a salt with the catalyst’s cation

What is the standardised name for gylcerol?

propane-1,2,3-triol

What are triglycerides?

Esters that are formed from a Glycerol backbone and three fatty acids (long carboxylic acid chains)

What are fatty acids?

Carboxylic acids with an even number of carbon from 12-22

What is a saturated fatty acid?

A fatty acid with only single bonds

What is an unsaturated fatty acid?

a fatty acid with double or tripple bonds.

Monounsaturated

1 double or triple bond

What reaction causes the formation of trigylcerides?

condensation

when a triglyceride is formed, the fatty acids are

not always the same

under acidic hydrolysis, triglycerides form

glycerol and fatty acids

under alkaline hydrolysis, triglycerides form

glycerol and carboxylate anions

Edible fats are mostly made up of

saturated fatty acids

In saturated triglycerides,

Hydrocarbon chains lie parallel, allowing for neat and ordered stacking

Why do hydrocarbons lie parallel in saturated triglycerides

The carbon’s geometry is tetrahedral, and changes in the presence of a double or triple bond

Saturated Triglycerides neat chains,

they have an increased dispersion forces between chains

Saturated Triglycerides have

a high melting point due to strong dispersion forces

Edible oils are mostly made up of

unsaturated fatty acids

Unsaturated triglycerides’ carbons have a combination of

tetrahedral and trigonal planar geometry

Unsaturated triglycerides’ double bonds

cause the trigonal planar geometry, as the chain twists.

Unsaturated triglycerides have

decreased dispersion forces due to their twisted chains not aligning neatly

Unsaturated triglycerides

have a lower melting point than saturated triglycerides

the general formula for a saturated fatty acid is

C_nH_2nO₂

for every double bond

2 hydrogen atoms are displaced

Bromine and iodine

undergo addition reactions and bond to hydrocarbons, changing double bonds into single bonds

Bromine turns from

colourless to brown when all double bonds are taken up

bromine/ iodine number is

the mass of bromine or iodine that reacts with exactly 100g of the compound.jhg

Bromine/ iodine number steps- finding iodine number

1 determine molar mass of iodine/ bromine and compound

2: arrange in a ratio of I₂:compound

3 divide both sides of the ratio by the compound’s molar mass to get a gram to gram ratio

4 multiply by 100 for grams of iodine or bromine used

Bromine/ iodine number steps- determining double bonds

1 determine moles of iodine/ bromine and compound present (mass/ molar mass

2: arrange in a ratio of I₂:compound

3 to get one mole of the compound, divide both sides of the ratio by the compound’s mole.

4 ratio is complete

Hydrogenation

The addition of H₂ molecules into a double bond, replacing them with single bonds