AQA Chemistry A-Level 3.3.1 Introduction to Organic Chemistry Detailed Notes PDF

AQA Chemistry A-level 3.3.1: Introduction to Organic Chemistry Detailed Notes https://bit.ly/pmt-edu 3.3.1.1 - Nomenclature There are different way of writing and representing organic compounds: 1. Empirical Formula - The simplest whole number ratio of at...

AQA Chemistry A-level 3.3.1: Introduction to Organic Chemistry Detailed Notes https://bit.ly/pmt-edu 3.3.1.1 - Nomenclature There are different way of writing and representing organic compounds: 1. Empirical Formula - The simplest whole number ratio of atoms of each element in a compound. 2. Molecular Formula - The true number of atoms of each element in a compound. 3. General Formula - All members of a homologous organic series follow the general formula. Example: 4. Structural Formula - Shows the structural arrangement of atoms within a molecule. Example: 5. Displayed Formula - Shows every atom and every bond in an organic compound. Example: 6. Skeletal Formula - Shows only the bonds in a compound and any non-carbon atoms. - Vertices are carbon atoms. - Hydrogen is assumed to be bonded to them unless stated otherwise. Example: https://bit.ly/pmt-edu Homologous Series Organic compounds are often part of a homologous series, in which all members follow a general formula and react in a very similar way. Each consecutive member differs by CH2 and there is an increase in boiling points as chain length increases. Example: 3.3.1.2 - Reaction Mechanisms These show the movement of electrons within a reaction, shown with curly arrows. Example: Mechanisms are used to show the reactions of organic compounds. https://bit.ly/pmt-edu 3.3.1.3 - Isomerism Isomers are molecules with the same molecular formula but a different arrangement of atoms within the molecule. Structural Isomers These have a different structural arrangement of atoms. They can be straight chains or branched chains but will have the same molecular formula. Example: Position Isomers These have the functional group of the molecule in a different position of the carbon chain. Example: https://bit.ly/pmt-edu Functional Group Isomers These have a different arrangement of the same molecular formula so that the molecule has a different functional group. Example: Stereoisomers These have a different spatial arrangement. A type of stereoisomerism is E-Z isomerism, where limited rotation around a double carbon bond means that functional groups can either be ‘together’ or ‘apart’. The E isomer (german for entgegen meaning apart) has functional groups on opposite sides. The Z isomer (german for zusammen meaning together) has functional groups together on the same side of the double bond. Example: https://bit.ly/pmt-edu Cahn-Ingold-Prelog (CIP) Priority Rules There is a priority of different groups in molecules that can display E-Z isomerism. The first atom which is directly bonded to the carbon with the double bond with the higher Ar is given the higher priority. These groups are used to determine if it is the E or Z isomer. Example: Therefore this molecule is the Z isomer as the highest priority atoms are on the same side. How to determine a more complicated E/Z isomers Compound A https://bit.ly/pmt-edu  Step 1: Apply the CIP priority rules ○ Look at R1 and R3: Carbon is the first atom attached to the C=C bond, on the left hand side ○ Look at R2 and R4: Carbon is the first atom attached to the C=C bond, on the right hand side ○ This means that we cannot deduce if compound A is an E or Z isomer by applying the CIP priority rules to the first atom attached to the C=C bond Therefore, we now have to look at the second atoms attached Step 2: Apply the CIP priority rules (using the second atoms) ○ Look again at R1 and R3: The second atoms attached to R1 are hydrogens and bromine The second atoms attached to R3 are hydrogens and another carbon We can ignore the hydrogens as both R groups have hydrogens Bromine has a higher atomic number than carbon, so bromine is the higher priority Therefore, the CH2Br group has priority over the CH3CH2 group ○ Look again at R2 and R4: The second atoms attached to R2 are hydrogens and chlorine The second atoms attached to R4 are hydrogens Chlorine has a higher atomic number than hydrogen, so chlorine is the higher priority Therefore, the CH2Cl group has priority over the CH3 group Step 3: Deduce E or Z ○ In compound A, the two highest priority groups are on the same side (both above) the C=C bond Therefore, compound A is the Z isomer https://bit.ly/pmt-edu