A2 Chemistry

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Module 1 (F324)  - 'Rings, Polymers & Analysis.' 

This module covers the properties and reactions of:

a) Arenes, b) carbonyl compounds, c) carboxylic acids and esters, d) nitrogen compounds,
e) stereoisomerism and organic synthesis, f) polymerisation, and g) spectroscopy .
  • Summary of the reaction mechanisms we'll cover in this unit. You'll need to learn these. Even better if you understand how they work - then you'll be able to apply them to any situaton the examiners may ask you about.
  • Animations of reaction mechanisms can be found here. Have a look, they might help you visualise what's happening to the electrons in a reaction.
  • More on reaction mechanisms. This site has notes and animations for the mechanisms we study.
  • Arenes:
    • Reactions of Arenes
    • Quick summary of arenes at S-Cool. Good starting point for revision. You will, however, need more depth and understanding to maximise your grade.
    • Pod Cast on Benzene. 5 minutes on the structure of benzene and why arenes usually undergo 'addition' reactions, rather than 'substitution' reactions - be careful! Kekule was wrong.
    • More on Benzene here. Really useful in-depth notes that could be a great starting point to make a concept map with this software. The site also includes links to AS organic chemistry, so you can be sure you are confident of your prior knowledge.
    • Concept Map
    • 'Active' revision notes.
    • N.B. You MUST understand & be able to explain the influence of the benzene ring (delocalised electrons e.t.c.) on reactivity.
  • Carbonyl Compounds

  •     Key point: a carbonyl group is a functional group composed of a carbon atom double=bonded to an oxygen atom : i.e. C=O.

    A2 study of carbonyl compounds divides into: 

    (1) reactions that apply to all carbonyl compounds, and 

    (2) reactions that apply only to aldehydes and ketones.

    1) Reactions of ALL carbonyl compounds:  

    • The reduction of carbonyl compounds (C=O) using NaBH4 or LiBH4 to form alcohols. Note that these reagents basically supply Hydrogen '[H]' to the carbonyl compound, to create a primary alcolol (aldehyde), or a secondary alcohol (ketone). In the exam, it is OK therefore to represent NaBH4 or LiBH4 as, for example with aldehydes and ketones, "2[H]". If there is more than one C=O group (however unlikely), more [H]'s will be needed in your equation. 
    • The use of 2,4-dinitrophenylhydrazine (everything you need to know is here)    (i) to detect the presence of a carbonyl group in an organic compound;    (ii) to identify a carbonyl compound from the melting point of the derivative. 
    • N.B. The equation for this reaction is not required.

    2) Reactions of Aldehydes and Ketones ONLY:

    • The mechanism for nucleophilic addition reactions of hydrogen cyanide (in the presence of potassium cyanide) with aldehydes and ketones. Click here to learn the reaction mechanism

    • The use of Tollens’ reagent (ammoniacal silver nitrate) (click here to find out why alhedydes & ketones behave differently with Tollens)

      • (i) to detect the presence of an aldehyde group;

      • (ii) to distinguish between aldehydes and ketones, explained in terms of the oxidation of aldehydes to carboxylic acids with subsequent reduction of silver ions to silver. 

    3) Concept map here
  • 4) Active revision notes Carbonyls-  Work through the notes & complete all the questions. 
  •                                                              Carboxylic acids & Esters                                                           
    • 1) Carboxylic acids as ACIDS - Notes on WHY carboxylic acids are acids and their reactions HERE.
    • 2) Carboxylic acid ==> ester - Notes on esters and how they can be made from a carboxylic acid & an alcohol HERE.
    • 3) Reactions of Carboxylic acids with PCl5 and SOCl2 to make acyl chlorides (R-Cl) -  Notes & equations HERE.
    • 4) Hydrolysis of esters by acids & alkalis - Notes HERE.
    • 5) Concept map - here
    • 6) 'Active' revision notes - here. Work through the nores & answer all the questions (use the links in this site if you get stuck)
  •                                                                    Amines... R-NH2                                                                    
    • 1) What is an amine? - Not essential for the course, but useful background - click here for notes.
    • 2) Preparation (synthesis) of amines - Notes HERE. You ONLY need to know how to make an amine from:
      • a) Nitrobenzene (C6H5NO2).
      • b) A nitrile (R-CN).
      • c) A halogenoalkane (R-X).
    • 3) Reactions of amines - You need to know:
      • a) Why are amines BASES? - click here, but ignore the reaction with copper(II).
      • b) Important!!! - why is phenylamine LESS basic than non-aromatic amines? Explanation is here (scroll down to 'Why is phenylamine such a weak base?'). Try your hardest to get your head around these ideas for the exam.
      • c) Synthesis of AZO dyes - learn the conditions & equations for this 2-step process: STEP 1 (sroll down to 'the reaction at low temperatures' - this makes a 'diazonium ION'),  STEP2. Note one or two USES of azo dyes.
    • 4) Amino Acids - You need to know:
      • a) The GENERAL formula of an amino acid is: RCHNH2COOH. As you can see, the 'amino' comes from the -NH2 functional group, and the 'acid comes from the -COOH group.
      • b) 'Acid-base' behaviour of amino acids & their ability to form 'ZWITTERIONS' - Notes HERE. 
      • c) Notes on the peptide link can be found here. You need to realise that this condensation reaction is able to polymerise amino acids into long protein chains. 
      • d) Acid hydrolysis of proteins - putting the water back in. Notes here.  
    • 5) Class concept maps - (synthesis of amines, reactions of amines, amono acids)
    • 6) 'Active' revision notes - HERE- work through & answer the questions as part of your revision
  •                                                  Stereoisomerism & Organic synthesis                                                 
    • 1) Stereoisomerism -
      • Notes on optical isomers here. 
      • Geometric (cis/ trans) notes here. 
    • 2) Organic Synthesis -
      • Adding a carbon to an aldehyde (RCHO) with HCN, followed by hydrolysis to a carboxylic acid (RCOOH). Notes here.
      • Synthetic reactions of Acyl Chlorides (RCOCl). You need to know 3 reactions (ALL addition-elimination, so the mechanism is the SAME): 
        • i) Acyl chloride (RCOCl) + alcohol (ROH) ==> Ester (RCOOR')
        • ii) Acyl chloride (RCOCl) + water (H2O) ==> Carboxylic acid (RCOOH)
          • Notes on the two reactions above can be found here.
        • iii) Acyl chloride (RCOCl) + Primary amine (R-NH2) ==>  N-substituted amide (RCONHR').     Notes here.  
    • 3) Concept map - HERE. 
    • 4) 'Active' revision notes - HERE. Work through each topic & answer all the questions. 
  •                                                                     Polymerisation                                                                  
    • 1) Addition Polymerisation - You need to know that alkEnes can be polymerised by addition to their double bond.  
      • Notes here. 
      • You MUST be able to define the terms "atactic, isotactic or syndiotactic". These refer to the optical activity of any given polymer. You can make your own notes by clicking here and scrolling down to "The three variations on this structure".
    • 2) Condensation Polymerisation - 
      • PolyESTERS - Terylene - (from benzene-1,4-dicarboxylic acid and ethane-1,2-diol) - notes. 
      • PolyAMIDES - Nylon & Kevlar - notes.
      • PolyPEPTIDES - How do amino acids form polymers to make proteins? - notes here.
    • 3) Concept Map - HERE. 
    • 4) 'Active' Revision notes - HERE. Work through the text & questions. Use this website for help if you need it. 
  •                                                                      Spectroscopy                                                                     
    • Syllabus note - IMPORTANT! - You are not required to understand HOW spectroscopy works. All you will be asked to do is interpret spectra OR (for NMR ONLY) say what spectrum you would expect from a particular molecule.
    • 1) Infra-red spectroscopy (IR) - From a given spectrum and data sheets, you have to be able to identify the presence of the following functional groups in an IR spectrum:
      • Alcohol (O-H)
      • Carbonyl (C=O)
      • Carboxylic acid (COOH)
      • Ester (COOR)
      • Notes: - IR spectra divide into 2 regions. The 'fingerprint' region, and troughs due to functional groups.
      • See also spectroscopy concept map.
    • 2) Nuclear Magnetic Resonance Spectroscopy (NMR) - From a spectrum, you must be able to predict:
      • The number of proton 'environments'  - from number of 'clusters'
      • The relative numbers of each type of proton (H) - from relative peak area (supplied on the question paper)
      • The number of protons (H) next door to a given proton - from spin-spin patterns (clusters) up to quadruplets.
      • The different types of proton (H) - from chemical shift values (supplied in the exam's data sheet).
      • The possible structure of a molecule.
      • You also need to be aware of how D2O (deuterium) can be used to elucidate the presence of an -OH group. 
      • Notes: - here. 
      • Concept map. 
      • Practice problems here.
    • 3) Mass Spectrometry - All you need to be able to do is USE a mass spectrum to determine the relative molecular mass of an organic molecule - SPECIFICALLY:
      • Use the MOLECULAR ION peak (M+) ro determine the Ar of a molecule. This is really easy, as these NOTES will show. Also see the grove chemistry spectroscopy concept map.
    • 4) 'Active' revison notes - Here (IR, MS, NMR). Be careful to identify the areas you need to focus on (use your syllabus).

Module 2 F325  - 'Equilibria, Energetics & Elements.' 

  •                                                            How Fast? (rates of reaction)                                                     
    • Revision: [Download a summary sheet here.]
      • Collison theory notes
      • Solids - changing the rate of a reaction through surface area - notes here.
      • Liquids - changing the rate of a reaction through concentration - notes here.
      • Gases - changing the rate of a reaction through pressure - notes here.
      • Temperature - how increasing temperature can increase the rate of a reaction - notes here.
      • Catalyst - if you add a catalyst you increase the rate of a reaction to find out how click here. 
      • Essential revision notes from AS that include Boltzmann distributions can be found here. Ask your teacher to indicate the relevance of each section to your exam board specification.
    • A2 stuff - an excellent active revision sheet can be downloaded here.
      • Orders of reaction & rate equations. 
        • Background notes here.
        • How to deduce the order of a reaction here 
        • Example rates calculations here.
        • Powerpoint presentations on 'basic' (AS) and 'advanced' (A2) kinetics can be downloaded here. Look for 'physical' and download 'Kinetics(1)' for basic and 'kinetics(2)' for advanced.
  •                                            How Far? (equilibrium & reversible reactions). 
    • Background
      • Basics of chemical equilibria here.
      • Le Chatelier explained here.
      • Bringing it all together - Haber process. Combines theories of chemical equilibria & rates of reaction.
    • A2 Stuff
      • Equilibrium constants in homogeneous reactions:- Kc (liquids) and Kp (gases)
      • The effects of changing conditions on equilibrium constants (here).
    • Calculations
      • Try some calculations here.
  •                                                               Acids, Bases & Buffers                                                               
  • A2 stuff
    • Bronsted-Lowry theory of acids & bases (notes here - scroll down). N.B! 'Arrhenius' & 'Lewis' theories are NOT required for this course.
    • Strong & weak acids (pH, Ka & pKa) notes here. Calculations here. 
    • Ionic product for water (Kw & pKw) here.
    • pH (titration) curves notes here. You need to be able to recognise these & deduce a suitable indicator.
    • 'How to choose the right indicator for a titration'. Notes here.
    • Buffers. Notes here. Calculations here.
  • Lattice Enthalpy
  • Video revision of Hess' law here and here.
  • Lattice enthalpy videos - part 1, part 2, part 3.
  • Brief (but useful) notes on wikipedia.
  •                                                                   Period 3                                                                               
  • Redox:
    • Definitions of oxidation & reduction - notes here.
    • Oxidation states (oxidation numbers) - notes here.
    • How to write IONIC equations for redox reactions - notes here.
  • Period 3 elements (Na to Ar)
    • Revision from AS - Physical & atomic properties of period 3 elements explained - notes here.
    • Reactions of period 3 elements with H2O, O2 and Cl2 - notes here.
    • Period 3 oxides -
      • Physical properties - notes here.
      • Reaction with water and acid-base properties - notes here.
    • Period 3 chlorides - physical properties & reactions with water - notes here.
    • Period 3 hydroxides- physical properties & reactions with water - notes here.
  •                                                                Transition Elements                                                           
  • Basic features & chemistry of transition elements - notes here.
  • Iron - notes here.
  • Copper - notes here.
  • Complex ions - 
Module 3 F326  - 'Practical Skills Assessments (PSAs).'
    •  Practice calculations below:
 

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