Organic Chem

Number of bonds per element

HONC

• H - 1

• O - 2

• N - 3

• C - 4

Hydrocarbon

organic molecule composed of only carbon and hydrogen atoms

saturated alkanes

have single bonds as the maximum number of atoms per C atom (4)

Homologous series

1. Must be in same family of organic compounds

2. each successive member of the group must change by the same unit

General formula of Alkanes

CnH2n+2

Molecular formula

number of each molecule

Structural formula

shows all bonds between atoms

Semi-structural formula

does not show single bonds but can show C to C double bonds

skeletal formula

does not show any atoms unless part of a functional group

• never shows carbons

Naming branched chain alkanes

1. Identify the longest chain

2. Identify and name side/branched chains (named at front)

3. Identify position of side chain. Number the carbons from end that gives side chain the lowest number. This is written at front.

Draw structural formula of branched chain alkanes

1. Draw the number of carbons on parent chain

2. Identify the position of side chain and draw carbons of the side chain

3. Add necessary hydrogens

Draw semi-structural formula

1. Draw structural formula

2. Side chains will be in brackets

Alkenes

Hydrocarbons with one or more carbon-carbon double bonds and are unsaturated (carbons that form double bonds are not bonded to the maximum number of atoms)

General formula of alkenes

CnH2n

Naming branched chain alkenes

1. Identify longest chain that contains the C to C double bond (position of double bond must be indicated)

2. Number the carbons starting from end that gives the double bond the lowest number

3. Identify side chain and indicate position of side chains

Structural isomers

Same molecular formula (same number and type of atoms) but different structural formula (arranged differently)

• Also have different mass and names

Cyclo alkanes

ring molecules based on an alkane

• eg. cyclopropane and cyclopentane

often drawn more simply with just shapes as skeletal and each carbon is a corner

Benzene

Functional Groups

A functional group is a specific atom or group of atoms within a molecule that gives the molecule characteristic chemical properties

• alkanes, side chains NOT functional groups

Haloalkanes

1. Halo groups have same priority as side chain

2. When multiple, name halo groups in alphabetical order

3. In semi structural formula they are in brackets

Same priority as alkyl branches

Naming compounds with single functional groups

1. Functional group has priority over any branches

2. Number from end closest to functional group

3. Use functional group suffix

4. If more than 3 carbons (4 for alkenes), include location

• EXCEPT: carboxylic acids, esters and aldehydes which don’t need location

Alcohols

contain a hydroxyl functional group

-ol suffix

family: alcohol

functional group: hydroxyl

when not highest priority: hydroxy

Types of alcohols

Primary, secondary or tertiary tells us how many C’s are bonded to the C that is bonded to the OH

Amine

NH2 (amino) group

-amine suffix (give location)

“amino” is used when not the highest priority functional group

Carboxylic acid

have a carboxyl functional group

-COOH

-oic acid (don’t need location)

highest priority always

Ester

COO

-oate

“yl” comes from alcohol which is the one without double bond O

“oate” comes from carboxylic acid which is the one with double bond

Ketone

CO

-one as suffix

always in middle

Aldehyde

-al as suffix (location not needed)

CHO (NOT COH)

Amides

primary = 2Hs to N

secondary = 1 H to N

Functional group priorities in the data booklet

Naming when multiple functional groups

1. Functional group with highest priority is assigned the lowest possible number and the suffix for the functional group is the same

2. the lowest priority functional group is indicated by prefix or alternative name

Name

Name

Name

If next consonant next to consonant

put in e

Properties of alkanes

-non-polar

-insoluble in water

-relatively malleable as dispersion forces are weak

-relatively low m.p and b.p

Melting and boiling point of alkanes

1. As no. of carbons increases, the melting and boiling point increases

2. Alkanes are non-polar so only have dispersion forces

3. As molecule gets larger, no. of electrons also increases so stronger dispersion forces

4. more heat energy is required to break them so higher b.p and m.p

Melting and boiling point between branched chain and straight chain alkanes

1. All alkanes are non polar so only dispersion forces

2. Straight chain alkanes can pack closely together so stronger dispersion forces and more heat energy required to break the forces, so higher m.p b.p

3. Branched chain alkanes cannot pack closely together so weaker dispersion forces and amount of heat energy required is less so lower b.p

Organic molecules in order of increasing b.p and m.p when similar in size

1. Alkenes and alkanes - non polar - dispersion forces only

2. Haloalkanes - polar - dipole-dipole

3. Alcohols - polar - H-bonding

4. Carboxylic acids - polar - H bonding

   • can also form dimers so stronger than alcohols

Intramolecular forces

bonds within molecule

• covalent

• strong

• hard to break

Intermolecular forces

Between molecules

• broken when states change

• weak

Hydrogen bonding

1. occurs between polar molecules

2. strongest IMF

3. occurs when H is bonded to N,O,F covalently and directly

Dispersion forces

1. all molecules have dispersion forces

2. due to formation of instantaneous dipole

3. large molecules have greater d.f as they have larger molar mass, meaning more e-

m.p and d.p dispersion forces

Larger molecule, higher Mr, more e-, stronger d.f, more heat energy required to break, higher m.p and b.p

Who undergoes addition reactions?

alkenes

Addition reactions

C to C double bond in alkene breaks and more atoms can be added to the carbons with the double bond

Addition reaction: adding halogens (eg. Cl2)

Addition reaction: adding hydrogen halides (eg. HCl or HF)

Addition reaction: adding hydrogen (H2)

Addition reaction: water (H20)

If alkene is unsymmetrical and 2 diff atoms/ groups added (eg. HCl, H20)

then you will get isomers

Substitution reaction

occurs when an atom or a functional group in a molecule is replaced or substituted by another atom or group

• ALWAYS GET A SIDE PRODUCT

Substitution reactions of alkenes

• Alkanes react with halogens

• One H swaps places with a halogen atom (we only learn about ones at end)

• CONDITION: REQUIRES UV LIGHT

Substitution reactions of haloalkanes

can occur with OH- base or ammonia (NH3)

Substitution reactions of haloalkanes with OH-

Substitution reactions of haloalkanes with ammonia (NH3)

Oxidation reactions

Alcohols undergo oxidation reactions when they react with an oxidant

• remember the gain of oxygen, loss of hydrogen part of oxidation

Oxidising agents for alcohol oxidation reactions

Oxidation of primary alcohols

Oxidation of secondary alcohol

Oxidation of tertiary alcohol

Do not undergo oxidation

• write like redox reactions ig

Condensation reactions

Reactions in which two molecules combine, usually in the presence of a catalyst, with elimination of water or some other simple molecule. A new covalent bond is formed.

• 3 types

3 Types of condensation reactions

esterification (condensation reaction that forms an ester)

Condensation reaction of carboxylic acid with ammonia

Carboxylic acid and amine

Hydrolysis of esters

condensation reactions can be reversed by hydrolysis

• ester broken down into acid and alcohol by adding water

What do percentage efficiency and atom economy tell you?

efficiency of reactions

Calculating percentage yield of multistep reaction

Atom economy

Atom economy for a chemical reaction is a measure of how many atoms in the reactant end up in the desired product

High atom economy?

Atom economy formula

Lower atom economy

High atom economy

1. Less environmental impact

   • fewer by-products so less waste generated

2. Better safety

   • by-products can be toxic and handling waste after is a hazard, so fewer by-products is safer

3. Reduced cost

   • less waste, less disposal and maintenance, may reduce overall cost

4. Better quality of product

   • fewer by-products means simpler seperation process so maybe higher purity

Sustainable chemical process

one that minimises environmental impact and consumption of non-renewable resources while maintaining or improving the economic and social benefits associated with the product

Renewable feedstocks

Catalysis

Designing safer chemicals