Chemistry - Chapter 11- Organic chem

Basic concepts of organic chemistry

Define organic compound.

A carbon- containing compound

Define hydrocarbons.

Compounds that consist carbon and hydrogen only

Define saturated

Orgainc compounds that have single bonds

Define unsaturated

Organic compounds that have double bonds

Define homologous series.

A series of organic compounds containing the same functional group with successive memebers differing by CH2s.

Define functional group

A group of atom responsible for the characteristic reactions for a compound

Define aliphatic

When carbon atoms are joined to each other in branched or straight chains with no aromatic rings.

Define alicyclic

When carbon atoms are joined to each other in ring structures (cyclic), with straight or branched chains and have no aromatic rings.

It is the combinition of cyclic and aliphatic

Define aromatic

Some or all of the carbon atoms that are found in a benzene ring

or

Organic compounds that contain a ring of atoms with altering double bonds- eg. Benzene

Define stem

The number of carbon atoms in the longest continuous chain in the molecule

Define suffix

the functional group that is attached after the stem

Define prefix

The side chains/ functional grouyp that is attached before the stem

Define general formula

The algebaric formula that represents the composition of a whole homologous series of organic compounds using letters and number

Define molecular formula

The actual number of atoms of each element in the molecule

Define empirical formula

The simplest whole-number ratio of atoms of each element in a compound

Define displayed formula

It shows the order in which atoms are bonded

Define structural formula

Minimal detail that shows the arrangement of atoms in a molecule

Define Skeletal formula

A line for each bond but no carbon atoms or hydrogen next to carbons are shown. All other atoms will be shown ( as functional group)

Name the stems from 1 to 10 number of atoms

1- meth

2- eth

3- prop

4- but

5- pent

6-hex

7- hept

8- oct

9- non

10- dec

What is the listed rule of nomenclature? (5)

1. Identify the longest carbon chain and determine the stem name

2. Identify the main functional group( prefix or suffix)

3. Number the carbons with the functional groups on the stem chain

4. Find if there are multiple prefix and name them with di, tri, tetre…

5. Arrange the prefixes in alphabetical order

What are the 10 main functional groups listed in the order from high to low priority/ precedence?

1. Carboxylic acids

2. Nitriles

3. Aldehydes

4. Ketone

5. Alcohols

6. Amines

7. Alkenes/ Alkynes

8. Alkanes

9. Haloalkanes

10. Alkyl groups-

What does having a higher priority mean?

means the functional group’s suffix will always be the priority than the ones that have a lower precedence

eg. Carboxylic acid- have a suffix of -oic acid will always be smt oic acid because it has the highest priority

What does the functional group of carboxylic acid consist and what are its suffix and prefix?

• Consist Carbon attached to O (in double bonds) and another single bond to OH

• -Oic acid

• Carboxy-

What does the functional group of Esters consist and what are its suffix and prefix?

• Carbon attached to an O with double bonds and another single bond attached to another O with a R group.

• -oate

What does the functional group of Amides consist and what are its suffix and prefix?

• Carbon attached to an O with double bonds and another single bond attached to NH2

• -amide

What does the functional group of nitriles consist and what are its suffix and prefix?

• Three bonds attached to a nitrogen

• -Nitrile

• Cyano-

What does the functional group of aldehydes consist and what are its suffix and prefix?

• A carbon attached to O (double bonds) and another single bond to H

• -al

• formyl-

What does the functional group of Ketone consist and what are its suffix and prefix?

• A carbon attached to O in double bonds

• -one

• oxo-

What does the functional group of alcohols consist and what are its suffix and prefix?

• Carbon attached to the OH group with single bond

• -ol

• hydroxy-

What does the functional group of amines consist and what are its suffix and prefix?

• Carbon attached to NH2 by single bonds

• -amine

• amino-

What does the functional group of Alkenes consist and what are its suffix and prefix?

• Double bonds between carbons

• -ene

What does the functional group of alkyne consist and what are its suffix and prefix?

• Triple bonds between carbon atoms

• -yne

What does the functional group of alkane consist and what are its suffix and prefix?

• Single bonds between carbon atoms

• -ane

What does the functional group of haloalkanes consist and what are its suffix and prefix?

• Halogens attached to stem

• no suffix

• Chloro, Bromo, Iodio, Floro

What does the functional group of alkyl consist and what are its suffix and prefix?

• Carbon atom with a hydrogen missing

• prefix- methyl, ethyl, propyl, butyl…

What does the functional group of ester consist and what is its suffix?

• Carbon linked to double bond to oxygen, a R group, another R group attached to an oxygen

• suffix: oate

What does the functional group of amides consist and what is its suffix?

• A carbon attached to NH2 and double bond to oxygen

• Suffix: amide

What does the functional group of alkynes consist and what is its suffix?

• A triple bond between two carbons

• Suffix- yne

Where is the priority around in the list for esters and amides?

Below carboxylic acid

Where is the priority around in the list for alkynes?

Around to the same priority of alkene (double bonds)

What is the general formula for cycloalkane?

Cn+H2n

What is the general formula for cycloalkene?

Cn+H2n-2

What is the general formula for alkane?

Cn+H2n+2

What is the general formula for alkene?

CnH2n

What is the general formula for Alcohol?

CnH2n+1 OH

What is the general formula for carboxylic acid?

CnH2n+1 COOH

What is the general formula for Ketones?

CnH2nO

What is the general formula for Alkyl?

CnH2n+1

Define Benzene

C6H6

Define structural isomers

Molecules that have the same molecular formula but different structural formula

Define the three types of structural isomers.

1. Chain isomer- carbon atoms arranged differently (differemt skeletal)

2. Position isomer- functional group attached to a different carbon on the same main chain

3. Functional isomers- Some compounds with the same molecular formula but with different functional group

Define homolytic fission

The breaking of covalent bond with one of the electrons going to each atom with an even split- which forms two radicals

Define heterolytic fission

The breaking of the covalent bond with both of the electrons going to the same atom with an uneven split, making a cation and an anion.

Define radical

Species with an unpaired electron

When does this fission happens?

When a chemical reaction occured and new bonds are formed when products are made while old bonds are broken in reactants

Define reaction mechanism

A step- by- step sequence that shows how bonds are broken and formed as reactants turn into products (using curly arrows)

What do curly arrows represents?

It represents the movement of electrons during a chemical reaction

How are heteroytic fission shown and why?

By double headed arrows- because it shows that both electrons are transferred

How are homolytic fission shown and why?

By single headed arrows- because it shows that one of the electrons are transferred to each atom

What does a single bond represents?

lone pairs/ two electrons

What are the three type of reactions?

1. Addition reaction

2. Substitution reaction

3. Elimination reaction

Define addition reaction

Where two or more molecules combine to form a single larger molecule by breaking double bonds (unsaturated) to attach with another atom (become saturated)

Define substitution reaction

Where an atom or a group of atoms is replaced by a different atom or group of atoms

Define Elimination reaction

The removal of small molecule from a larger one (one reactant forms two products)

What is alkane?

A saturated hydrocarbon that are linked by single bonds/ sigma bonds which have the general formula of CnH2n+2.

Define sigma bond.

A bond that is formed from two direct overlap between two orbitals from two different atoms ( one electron comes from each bonding atoms, forming an area with shared electrons)

Desecibe a property of sigma bonds and why it is allow to do that.

They are free to rotate- due to a cylindrically symetrical districbution of electron density.

Describe the shape and bond angle of alkanes.

Alkanes are tetrahedrals as each carbon has four valence electrons. Bond angle= 109.5.

Explain how different structures of alkane can affect its boiling point (2).

1. Chain length- The longer the length of an alkane chain, the higher boiling point. This is due to a larger contact surface area for London forces/ induced dipole dipole forces between molecules. More energy is required to overcome these forces.

2. Branching- The more branching there are in alkanes, the lower the boiling point. This is because of the smaller contact surface area between molecules which means less London forces. Less energy is required to overcome the forces between molecules.

Describe the reactivity of alkanes (3).

Alkanes have low reactivity/ stable because

1. C-C and C-H bonds are strong sigma bonds- high bond enthalpy (energy required to break 1 mole of gaseous bond)

2. C-C bonds are non polar- there are no difference in electronegativity

3. C-H bonds are also non polar- little and similar electronegativity

Describe how alkanes undergoing complete combustion can act as a fuel. (3)

1. Easy to transport

2. really available in natural resources- can be fractional distillated to acheive

3. Produce large amount of heat without creating toxic products (only water and carbon dioxide)

Explain why incomplete combustion is bad?

Incomplete combustion happens when there is a limited supply of oxygen, forming CO or carbon and water.

Carbon monoxide is odourless and colourless but can bind to haemoglobin and replace oxygen. Cause the lack of oxygen supply to body.

Explain free radical substitution in alkanes.

When the hydrogen in alkane is replaced by halogens in the presence of UV light.

Explain why free radical substitution only happens when there are UV light.

Because UV light provide high energy that breaks the covalent bond in the halogen molecule to start the reaction.

Describe the mechanism during free radical substition. (3)

1. Initialtion- Where UV light break halogen’s covalent bonds. Two halogen radical forms by homolytic fission where electrons are split equally.

2. Propagation- Where radicals react with other species/ alkanes to form alkane radical (missing one hydrogen) and hydrogen halide (HX). The alkane radical then react further with a halogen to from the product needed/ alkane(missing hydrogen) halide and a halogen radical. radical is regenerated.

3. Termination- Final step where the radicals can combine into different possibles and form different types of products (stable molecules).

What are the three main limitations of free radical substitution.