HOW TO WIN VCE - Chemistry 3&4.docx.docx

-( #) () () (((o(**)o))) HOW TO WIN VCEChemistry 3/4//You may get a viewing mode error. Try refreshing or coming back later. Its likely due to the large traffic on this page (Weve been pushing over the optimum cap of 50 viewers everyday)Feel free to add any information that will help benefit us all XDWELCOME :D TO BE A CONTRIBUTOR, comment/message me your gmail (francisle1997@gmail.com) :D May the VCAA odds be ever in your favour.Contributors:Arman Haque (original owner, thanks him the most)Shoshi R.Jordan W.Paras B.Young Y. Big thanks to all contributors, this has helped a lot of people :)Key:Red text = under speculation. may not be accurate.

Unit 3Chemical EquationsRedoxDefinition in terms of oxygen: Oxidation is gain of Oxygen Reduction is loss of Oxygen Oxidant is a substance that oxidises something else (oxygen donor) Reductant is a substance that reduces something else (oxygen acceptor + remover)

Definition in terms of Hydrogen: Oxidation is loss of Hydrogen Reduction is gain of hydrogen Oxidant gives oxygen to another substance or removes hydrogen from it Reductant removes oxygen from another substance or gives hydrogen to it (bolded definitions are good for organic chemistry only, otherwise stick with OIL RIG)Text book: Oxidation is defined as the loss of electrons. Similarly, reduction, is earlier defined as the loss of oxygen, it is more broadly defined as the gain of electrons.Definition in terms of Electrons: Oxidation is loss of electrons Reduction is gain of electronsAN OIL RIG CATOxidation is LOSS (OIL)Reduction is GAIN (RIG)AN OIL -> Oxidation at the AnodeRIG CAT -> Reduction at the Cathode

oxidant takes electrons from the other substance Reductant give electronsDefinition in terms of oxidation states Oxidation involves an increase in oxidation state. Atom becomes more positively charged. Reduction involves a decrease in oxidation state. Atom loses protons/gains electrons so becomes more negative/ less positively charged.

First identify which is the Reductant or oxidant (unless you are determining via oxidation states. Identify the change in oxidation number, then determine whether oxidation or reduction occurs, then identify the Reductant/oxidant if you feel like it) Reductant/Reducing agent -> removes oxygen , gives hydrogen, gives electrons to other substance Oxidant/Oxidising agent -> gives oxygen, removes hydrogen, removes electrons from other substance Then determine what happens to the substance Reductant/Reducing agent -> undergoes oxidation Oxidant/Oxidising agent -> undergoes reductionTypes of Equations1. Whole equation (perhaps with enthalpy information)a. Includes all reactants and products in the reaction including spectator ions2. Ionic equationsa. Only looks at the reacting ions3. Electron half equations a. Looks individually from the point of view from each ion in terms of its electron loss and gain Each type of equation can and should include states (aq, l, g, s) Single arrows are used to describe the change observed or are concerned with Reversible arrows means you are concerned with both the forward and backward reaction As in the case with equilibrium problemsWriting half equationsTo write half equations, four steps can be used:1. Balance all atoms in the half equation except for oxygen and hydrogenMnO4- > Mn2+

2. Balance the oxygen by adding waterMnO4- > Mn2+ + 4H2O

3. Balance the hydrogen atoms by adding H+ ionsMnO4- + 8H+ > Mn2+ + 4H2O

4. Balance the charges on both sides of the equation by adding electrons to the more positive side. Add states.MnO4-(aq) + 8H+(aq) + 5e- > Mn2+(aq) + 4H2O(l)To write an overall equation, add the oxidation half equation to the reduction half equation, making sure that the number of electrons used in reduction equals the number of electrons released during oxidation. If not, one of the half-equations must be multiplied to obtain a balanced number of electrons. In addition, the electrons, H+ and water molecules are cancelled.IF YOU ARE IN AN ALKALINE ENVIRONMENT, DONT STOP HERE. Add OH- ions to both sides to equal the highest amount of H+ on either side. Convert the H+ and OH- into water then cancel out the waters. Of course, if it is obvious that adding OH- will balance the equation, just do that instead of adding H+ to begin with. For exampleFe(OH)2 Fe(OH)3Clearly adding OH- will balance this equation, so dont go through the whole process of adding H+. Be logical, dont be a robot.Fe(OH)2 + OH- Fe(OH)3 + eThen, recheck that everything is balancedIMPORTANT HALF EQUATIONS TO REMEMBER (You will see these a lot as permanganate and dichromate are popular catalysts):Reduction of the permanganate ionMnO4-(aq) + 8H+(aq) + 5e- Mn 2+(aq) + 4H2O(l)Reduction of dichromate(VI) ionCr2O72-(aq) + 6e- + 14H+(aq) 2Cr3+(aq) + 7H2O(l)

Oxidation statesDefinition: The total number of electrons with have been removed from an element (positive oxidation state) or added to an element (negative oxidation state) to get to its present state.Oxidation involves an increase in oxidation stateReduction involves a decrease in oxidation stateTHE RULES TO IDENTIFY OXIDATION NUMBERS: Oxidation state of an uncombined element is zero Sum of oxidation states of all atoms or ions in a neutral compound is zero The sum of the oxidation states of all atoms in an ion is equal to the charge on the ion. Most electronegative element in a substance is given a negative oxidation state. The less electronegative is given a positive oxidation state. (Fluorine most electronegative, next is oxygen) Some elements always have the same oxidation number Group 1 metals always +1 Group 2 metals always +2 Oxygen - usually -2 (except in peroxides) H2O2 oxygen is -1 Na2O2 oxygen is -1 F2O oxygen is +2 (because fluorine is more electronegative) Hydrogen usually -1 (except in metal hydrides where it is +1) Fluorine always -1 Chlorine usually -1 (except in compounds with O or FWays to work it out Simple ion, ox num the charge Identify constant ox nums, then calculate In a compound, If no constant ox nums, identify the valency or each ion

Chemical AnalysisWhat is Chemical analysis? Chemical analysis, the study of the chemical composition and structure of substances. More broadly, it may be considered the collection of all techniques whereby any exact chemical information is obtained. Mole CalculationsNon instrumental techniquesGravimetric Analysis: Quantitative analysis based on differences in massMeasuring water content:Can be useful to determine the percentage of water in a given sample. This can be done by1) finding the mass of the initial sample 2) Heating the sample above 100C so that water turns into vapour. (about 110)3) Allowing the sample to cool in a dessicator so that the water evaporates.4) Finding the mass of the sample5) Repeating the heating/cooling/weighing process until a constant mass is achieved.VolumetricVolumetric analysis is a useful technique when the endpoint of a reaction between two Solutions can be easily observed. In acid-base titrations an appropriate indicator solution must be added, although an indicator is not usually required in redox reactions.

The aim of volumetric analysis is to determine the concentration of an unknown solution.A standard solution is one where the concentration is known accurately. The concentration of a primary standard is known because the required mass of a solid has been accurately weighed, then dissolved in a known volume of water. The concentration of a secondary standard has been determined by titrating it against a primary standard, Since the amount of a primary standard must be accurately weighed from its mass, it must have the following properties. Readily available and inexpensive in pure form Molecular formula must be known and must not vary eg) Moisture or other gases must not be absorbed from the atmosphere. gases must not be given off to the atmosphere. Must be easily stored without deterioration or reaction with the atmosphere Molecular mass should be relatively high to minimize weighing errors. It must be soluble and react according to a known chemical reaction. How its done:1) A pipette is used to transfer an aliquot of one of the solutions into a conical flask.2) The other solution is dispensed from a burette, into the conical flask. The volume that is dispensed from a burette is called the titre, and an average litre is used to minimise experimental error.3) The titration is stopped when the endpoint is reached, which is when the solution changes colour (an indicator solution may be required). This is just a drop hopefully after the equivalence point is reached, which is when the solutions have been mixed precisely in the mole ratio represented in the balanced chemical equation for the reaction.To get the average, use three concordant results which were all within 0.10ml (some experiments go even finer) from lowest to highest.

Chromatographic techniquesUsed to separate mixtures into substances. Uses knowledge of bonding and molecule size.The intermolecular bonds between substances is determined by the functional groups present and size. If functional groups of all substances are the same, then size will determine the Rf or Rt factor.

Understanding the difference between Retention time and retardation factor is essential. VCAA has emphasised this and they regularly test the students understanding of the differences in multiple choice questions.

TLC - Thin layer chromatographyThin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of glass, plastic, or aluminium foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose. This layer of adsorbent is known as the stationary phase.After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action. Because different analytes ascend the TLC plate at different rates, separation is achieved.Thin-layer chromatography can be used to monitor the progress of a reaction, identify compounds present in a given mixture, and determine the purity of a substance. (yes, i have blatantly copied that out of wikipedia but it very well sums up what you need to know http://en.wikipedia.org/wiki/Thin-layer_chromatography)Rf (retardation factor)- The retardation factor is a ratio of how far a particular substance traveled from the origin, compared to how far the solvent travelled.

As the Rf quantity is merely a ratio, the units become redundant.

Note: The lower the retardation factor, the less the substance travelled.Note: When youre performing TLC, you want to make sure that the solvent front never completely makes it to the top of the stationary phase.Measure how far it has moved from the centre of the spot.The less the solvent has moved the more attracted it is the the stationary phase. If it has moved further down, it is more attracted to the mobile phase. If the mobile phase is polar/hydrophilic, and the stationary phase is hydrophobic and the rf value of the solvent is high, you would say it is hydrophilic. If rf value is low, then its hydrophobicHPLC High Performance Liquid Chromatography This form of chromatography makes use of the retention time as opposed to the retardation factor. GLCCarrier gases:Any noble/inert gas can be used as a carrier gasRt (retention time)This is the time taken for a substance to travel through the column Spectroscopic techniquesEach of these techniques interacts at some level with the substance on the Electromagnetic spectrum.Spectroscopic techniques are used to identify substances rather than separateAASmetalsnMridentify environmentsC13 H1align with magnetic fieldIRaffects bonds between atoms.vibrates, stretchesUV-Vis/COLOURIMETRYcoloured solutionsusually coloured metalsMass Spectrometryionises, fragments and propels a substance.identify mass of each fragment to suggest groups presentalso to identify presence of isotopesOrganic ChemistryStructure and Nomenclature

Reactions

DNA DNA (deoxyribonucleic acid) is found within the nucleus. DNA is packaged with 46 chromosomes, which consist of genes. DNA is a condensation polymer made of four different monomers called nucleotides. The polymer is called a polynucleotide. Each nucleotide is made up of a phosphate group, deoxyribose sugar group and one of four bases (Adenine, Thymine, Cytosine, Guanine)

Adenine and Guanine are purine bases two rings Thymine and Cytosine are pyrimidine one ring.Primary StructureNucleotides are joined together in a long chain, where the phosphate joins onto the deoxyribose sugar on the fifth (5th) carbon and the third (3rd) carbon. The base joins onto the first (1st) carbon.[Note: the first carbon starts on the right of the oxygen.]

Secondary Structure:Two DNA polynucleotide strands are held together like a ladder by hydrogen bonds, and this ladder then twists to form a 3D double helix shape. These hydrogen bonds are between the base pairs; Adenine + Thymine and Cytosine + Guanine (AT and GC).

Between Adenine and Thymine, there are 2 hydrogen bonds Between Guanine and Cytosine, there are 3 hydrogen bonds.

Organic Reaction PathwaysDiagram by Jordan W

Condensation - Lipids/fats Fats: solid at STP Oils: liquid at STPThey are: Non-polar and hence insoluble in polar solvents Contain ester functional groupFats are made from a condensation reaction between Fatty Acids (-COOH group) and glycerol (-OH group), and the COO- linkage is known as the ester linkage.

Terms: Monoglyceride 1 fatty acid Diglyceride 2 fatty acids Triglyceride 3 fatty acidsSaturated: all single bonds (no C=C), Hence the name saturated. It is saturated with the max amount of hydrogens possible. Higher melting temperature than unsaturated. solid at STP, animal fats, has general formula CnH2n+COOH Monounsaturated: one double bond (C=C bonds), general formula CnH2n-1+COOH Polyunsaturated: two or more double bonds (C=C bonds), general formula CnH2n-3+COOH (not necessarily, depending on how many double bonds it has) usually liquid at STP more reactive than saturated fats (more double bonds) vegetable oilsWhy are saturated fats solid at room temperature?The more saturated the chains, straighter chains, the more closely they can align and therefore the stronger the dispersion forces between each molecule and its neighbours. Double bond in unsaturated fats will disrupt shape of chain therefore they cannot pack as tightly together (dispersion forces have to act over a greater distance). Also the longer the chains, the stronger the dispersion forces between the molecules.

Condensation and Polymerisation - Carbohydrates Carbohydrates have a general formula of Cn(H2O)mCarbohydrates can be classified as: Disaccharide: 2 units Oligosaccharides: 3-10 units Polysaccharide: >10 unitsMonosaccharides: Soluble in water therefore are polar and can be dissolved in polar solvents Atoms are arranged in a ringTypes of Monosaccharides:

Disaccharides: They are formed from two monosaccharides in a condensation reaction between two hydroxyl groups (-OH) on adjacent monosaccharides (forming an ether functional group or glycosidic link) Dissolves in waterFermentation of glucose: C6H12O6 -> 2C2H6O + 2CO2Types of Disaccharides:Maltose (2 glucose) Lactose (galactose + Glucose) Sucrose (glucose + Fructose)

Polysaccharides: They are carbohydrate polymers many monosaccharides linked in a chain Insoluble in waterTypes of Polysacchrides: Starch a polymer of glucose (straight chains) Glycogen a polymer of glucose (has branching) Cellulose starch and glycogen molecules are bonded together with hydrogen bonding in parallel chains, which are strong and water-insoluble fibres.

Why is glucose highly soluble in water?Due to the polar water molecules attached to the glucose molecules. The numerous -OH (hydroxyl) groups in glucose are normally attracted to the water molecules by dipole-dipole forces. The force's strength can be greater compared to the glucose -glucose interactions. The hydrogen bonding between water molecules and glucose also makes the glucose more soluble in water.

Biochemical Fuel Production

Medicine Synthesis - Aspirin

Unit 4

Rates of Reaction

Collision TheoryTemperature effect on ratePressure effect on rateconcentration effect on ratecatalyst effect on rateA catalyst increases the rate of a reaction by lowering the activation energy. Remember that a catalyst is not used in the actual reaction and does not undergo any permanent chemical change. When writing a chemical reaction, write the catalyst on top of the arrow to show it is not inc in reaction.

Energy Profile Diagrams

delta H - Change in heat enthalpy+ve delta H=endothermic reaction. Heat Energy has been absorbed by bonds hence it feels cooler.-ve delta H=exothermic reaction. Heat energy has been released by the bonds into the environment hence it feels warmer. WARNING: It is easy to get confused here. People may think, oh its hotter so there is more heat energy hence delta H +ve. this is wrong. It is hotter because heat energy was released into environment. So there is less heat in the actual bonds.

The above is an example of an exothermic reaction.calc delta H from energy profile

Equilibrium

Energy Sources - renewable

CalorimetryA calorimeter is an instrument designed to measure the change in heat of a chemical reaction when a specific heat capacity value is not known, and thus ultimately calculate H.A solution calorimeter is used for aqueous chemical reactions, whereas a bomb calorimeter is used for gaseous chemical reactions.

The calorimeter is an excellent insulator, and hence disallows heat energy to escape or heat energy to be gained from the environment (surroundings). However insulation can be a source of error in a practical investigation using calorimetry.Calorimetry Formulas Energy (J) = SHC (Jg-1K-1) x Temperature Rise x Mass (g) E = SHC x T x m CF = Calibration Factor, V = voltage (V), I = current (A), t = time (s), T = change in temperature (C or K)

Energy Change (J) = CF x T E = CF x T (Note: H is in J/mol, however sometimes the amount of mol cannot be calculated and therefore is in J/g) Be carful when giving the answer for the H of a reaction If the temperature increased it is exothermic, and hence needs to be ve. If the temperature decreased it is endothermic, and hence needs to be +ve. Heat of combustion: is the energy released when a specific amount of substance burns completely in oxygen

Electrochemical Series

Galvanic CellsA galvanic cell is a chemical system that produces an electrical current from a spontaneous redox reaction.An example of a half-cell:

(Note: electrons flow from ve to +ve)The Anode is negative (like an anion) and that is where oxidation occurs [AO-]Anions flow towards the anodeThe Cathode is positive (like a cation) and that is where reduction occurs [CR+]Cations flow towards the cathode

The Purpose of the salt-bridge: Complete the circuit allow charged particles to move Supplies ions each half-cell to maintain electrical neutralityCriteria of a salt-bridge: Highly soluble Conducts electricity Must not undergo any reaction with half-cellsThe Standard Electrode Potential or E0 value are compared to the SHE (Standard Hydrogen Electrode) and performed at standard conditions (1 atm, 25C, 1.0M solution)To work out the Cell EMF or voltage:EMF = E0(oxidant) E0 (reductant)(or work out the difference in E0 values larger minus the smaller)Primarycannot be recharged because the products of discharge move away from the electrodes (stub...will expand)SecondaryAble to be recharged my reversing the reaction. The reaction is reversed by supplying enough electricity to force a reverse reaction (stub...will expand)Fuel CellsIn a fuel cell, reactants are continually supplied allowing constant production of electrical energy and have up to an 80% efficiency. However they do produce waste energy, but it can be utilised by using the heat energy to produce steam and power a turbine.What are the advantages of fuel cells? It is environmentally friendly as no CO2 is produced - low pollution (only for a hydrogen/oxygen fuel cell) The fuel cell is more efficient than burning hydrogen or oxygen, as it has less transformations of energy (ie, doesn't go chemical E --> heat/light/sound E --> mechanical E --> electrical E, it goes straight from chemical E --> electrical E) Electricity is generated on site - therefore no need to connect to a power grid Can be recharged (unlike batteries) Quiet when running - unlike a generator or coal plant, etc What are the disadvantages of this fuel cell? Expensive to run - electrolytes and catalysts are expensive For domestic use, an inverter is needed to convert the direct current produced into a usable alternating current Produces DC voltage, not AC, which is used in homes Fuel cells rely on constant and reliable supply of fuel Roles of the electrode: To catalyse the reaction - increases the surface area for the reaction to take place, and hence increases reaction rate To conduct electricity and allow for electrons to flow to the external circuit Features of electrode: Chemically inert Porous Writing redox equations for fuel cells in an alkaline environment:K balance key elementO balance oxygen with H2OH balance hydrogen with H+4. put same number of OH- as H+ on both sides of equation5. turn H+ and OH- into H2O6. cancel out H2OE balance charge with electronsS states Electrolytic Cells

Faradays LawsFaradays 1st Law of Electrolysis: The mass of metal produced at the cathode is directly proportional to the quantity of electricity passed through the cellm QQ = I x t Faradays 2nd Law of Electrolysis: in order to produce one mole of metal, one, two, or three moles of electrons must be consumed.Q = n(e-) x FQ = n(e-) x 96500[Q = charge ( C), I = current (A), t = time (s), = proportional to]EXTRA GOODIESUsing The Data BookFresher up on bonding typesIntermolecular: Bonds between moleculesDispersion ForcesDipole-dipole Hydrogen bonda Hydrogen bond is a dipole bond made super because it is hydrogen :DWhen Hydrogen is bonded with certain elements, it strengths the dipole-dipole bond it forms between other molecules.Remember NOF:Nitrogen, Oxygen, Fluorine Have F,O,NIntramolecular: Bonds within the molecule itself (between atoms)IonicCovalentMetallic

Dissolution

CONCEPT SHEETVCE CHEMISTRY 3/4 IMPORTANT CONCEPTS, FACTS AND RULES This cheat sheet is intended as a checklist of things to be familiar with most of these pointers are focussed and a basic understanding of chemical terminology and concepts is assumed. Common problems that are addressed in the exam are highlighted in yellow. As a general rule of thumb, the content covered in Unit 4 is quite more finicky than that of Unit 3. Equilibrium and electrochemistry are relatively conceptually difficult and I have done my best to indicate rules that are set in stone. Good luck!ACID/BASE CHEMISTRYBronsted-Lowry Acid: Proton (or H+) donorBronsted-Lowry Base: Proton (or H+) acceptor Self-ionisation of water:

(at SLC) (note: is 1E-14 in calculator speak, NOT 10E-14)(at SLC) Strong acid: Completely dissociates to form H+ and conjugate baseStrong base: Completely dissociates to form OH- and conjugate acid Weak acids/bases partially dissociate into constituents based on ka (and kb) constants. (for monoprotic weak acids, which are typically the only case covered in VCE)

(water is ignored in equilibrium expression as [H2O] is huge and doesnt change by much) But typically according to stoichiometry of the given equation, so:

No need to memorise rearrangements. It is far more reliable to derive from the ka reaction equation. A strong acid/base will react with a weak base/acid to completion. It forces dissociation of the weak base/acid. Acid/base reactions do NOT involve electron transfer (redox). In other words there are no changes in oxidation state.OXIDATION/REDUCTION CHEMISTRY Note: The following definitions are in order of importance. Redox is about electrons!Oxidation:-The removal of electrons-The increase in a substances oxidation number-The addition of oxygen-The removal of hydrogen Reduction:-The addition of electrons-The decrease in a substances oxidation number-The removal of oxygen-The addition of hydrogen Oxidation number/state rules:-H is always +1 except in metal hydrides (XH) where it is -1-O is always -2 except in peroxides (X2O2) where it is -1 (because of above rule) Balancing typical half equations in aqueous solution:1. Add H2O to balance Os2. Add H+ to balance Hs3. Add electrons to balance charges Redox reactions need to happen in an acidified environment when H+ is a required reactant.STOICHIOMETRYVolumetric Analysis: Quantitative analysis based on measuring solution volumes.Titration:1. Diluting solution or dissolving substance to be analysed in volumetric flask2. Preparation of aliquot (with pipette into conical flask) and titrant of known concentration (in burette)3. Adding suitable indicator to aliquot (required in acid/base titration)4. Titration (add titre to aliquot until point of colour change concordant volumes of titre recorded)5. Stoichiometric calculations to find original quantities Washing procedures:-Wash volumetric flask with water (solvent)-Wash pipette with solution in volumetric flask-Wash burette with titrant-Wash conical flask with water (solvent). Does not matter if still wet Titration can be done with either acids/bases or a redox pair. Acid/base titration requires a pH indicator, and redox reactions may require a redox indicator if the reaction itself does not produce a colour change. Endpoint: Point of colour change (purely subjective)Equivalence point: When the amount of titrant added is stoichiometrically proportional to the amount of analyte in aliquot. In other words, when the titre is proportional to the aliquot concentration (based on coefficients in the reaction equation). This typically may not occur at pH 7. Gravimetric Analysis: Quantitative analysis based on measuring mass of a solid.Procedure:1. Dissolving original solid sample (of known mass) in solvent2. Reacting solution with excess reagent to produce precipitate3. Filtering precipitate from solution, washing and drying solid4. Weighing of final product5. Stoichiometric calculations to find percentage by mass of reacted substance in the solid sampleIDEAL GASESCombined gas law: PV = nRTUnit consistency: kPa L or dm3 Pa m3Partial pressures: PT = p1 + p2 + p3 + Gas constant: R = 8.31 J K-1 mol-1 (in data booklet) Ideal gas assumptions:-Molecules have no volume (are point masses)-No intermolecular forces-Kinetic energy is conserved with molecule/molecule or molecule/wall collisions Least ideal conditions:-Low temperature (significance of intermolecular forces)-High pressure (proportion of molecule volume to vessel volume) KINETICSTypes of kinetic energy:1. Vibrational2. Translational3. Rotational Factors for successful reaction to occur:1. Collision must occur2. Sufficient kinetic energy to overcome activation barrier3. Correct orientation/alignment Factors that change reaction rate:1. Number of molecules exposed for collision (eg. Surface area)2. Catalyst3. Pressure4. Concentration5. Temperature Which may affect:1. Frequency of collisions2. Proportion of energetically qualified collisions3. Proportion of correctly orientated collisions Reaction rate is dependent on frequency of successful collisions. Catalysts provide an alternate reaction path with lower activation energy, increasing reaction rate but not affecting equilibrium. Increasing temperature increases both collision frequency and proportion of energetically favourable collisions, but the latter has the greatest effect of increasing reaction rate.ORGANIC PATHWAYSSubstitution:-Chlorination Cl2 (g) of alkane with UV light-Hydroxide (aq) substitution of haloalkanes, heated under reflux Addition:-Hydrogen halide (g) addition to alkene (l or g) at room temperature-Halogen (g or l) addition to alkene (l or g) at room temperature-Water (g) addition to alkene (usually g) with catalyst at special conditions-H2 (g) addition to alkene (usually g) with Ni, Pt, Pd catalyst at special conditions Condensation:-Esterification: alkanoic acid (aq/l) and alcohol (aq/l) with acid at room temperature to produce an ester Oxidation:-Primary alcohol (aq) and oxidant (Cr2O72- (aq), MnO4-(aq)) with acid to produce alkanoic acid (aq)(OR secondary alcohol, producing ketone) Polymerisation:-Addition: Requires C-C double bonds in monomers, no other products formed-Condensation: Requires (typically) both hydroxyl and carboxyl groups on monomer, H2O formed as a by-product Qualitative tests:-Reaction with carbonate compound OR strong base (if bubbles, -COOH group present)-Reaction with bromine (if brown colour disappears, double bonds present) Cracking: Heating a hydrocarbon to high temperatures to produce multiple smaller hydrocarbons - these can be separated by fractional distillation Aspirin production: Reacting salicylic acid with ethanoic anhydride (if ethanoic acid is used, aspirin is hydrolysed by water product and yield is not high) BIOMOLECULESCarbohydrates:-Contains C, H and O-Simple unit: Monosaccharide (eg. glucose)-Reaction: Condensation between -OH bonds to form ether linkages (possible polymers)-Examples: Starch, cellulose, glycogen-Purposes: Energy storage, cell walls Fermentation of carbohydrate: carbohydrate ethanol + carbon dioxide(Yeast catalyst, and (usually) oxygen free environment required) Lipids:-Contains C, H and O-Simple unit: Glycerides, made of: -Glycerol -Fatty acids (long chain carboxylic acids)-Reaction: Condensation between -OH on glycerol and -COOH to form (tri)glycerides with ester linkages-Purposes: Insulation, energy storage Saturated fatty acids: CnH2n+1COOHUnsaturated fatty acids have C-C double bonds and therefore less Hs than in above formula Proteins:-Contains C, H, O, N and other elements-Simple unit: Amino acids-Reaction: Condensation between COOH and -NH2 to form peptide (amide) linkages-Examples: Insulin, haemoglobin, myoglobin In an amino acid, the -COOH end is acidic and the -NH2 end is basic. Will be affected by an acidic or basic environment (proton donation/accepting). At a certain pH, amino acids may exist with both COO- at one end and NH4+ at the other end Zwitterionic form. Primary structure: Peptide chain. Generally not affected by heatingSecondary structure: Adoption of shape (often helix) from H-bonding of (non-adjacent) peptide links. Affected by heatingTertiary structure: Folding of secondary structure into unique 3D shape, held by more H-bonding and disulfide links. Affected by heatingQuaternary structure: Aggregation of multiple tertiary structures Proteins are very high in molar mass usually analysed with HPLC. Enzymes are proteins that behave as biological catalysts. At lower than optimal temperatures enzymes are inactivated (frozen) and can be reverted to function normally with temperature increase. At higher than optimal temperatures, secondary and tertiary structures are permanently disrupted and enzymes become denatured. Nucleic Acids:-Contains C, H, O, N and P-Simple unit: Nucleotides, made of: -Nitrogenous base (A, C, G, T) -Five-carbon sugar (ribose and deoxyribose) -Phosphate-Reaction(s): Condensation between all components to form: -Phosphodiester links (covalent) between ribose/deoxyribose sugars -Covalent C-N bonds between ribose/deoxyribose and nitrogenous base-Purposes: Genetic code, cell function-Examples: DNA, RNA

DNA and RNA differ by:-DNA is double stranded, whereas RNA is usually single stranded.-Which five-carbon sugar is used (DNA deoxyribose, RNA ribose. Hence the naming scheme).-RNA uses Uracil in place of Thymine.

Primary structure: Nucletide chains (phosphate/ribose backbone held together by covalent bonds)Secondary structure: Double helix, formed from H-bonding between corresponding nitrogenous bases of two nucleotide chains.Tertiary structure: Complex 3D shape.

Adenine and Thymine pairs form 2 H-bonds each, and Guanine and Cytosine pairs form 3 H-bonds each. This makes DNA/RNA strands with a higher proportion of GC pairs more resistant to heat.SPECTROSCOPYFlame test:-Qualitative, for metallic composition-Valence electrons are elevated to higher energy states and emit light when returning to ground state. These frequencies and therefore flame colour are unique to what metal is present. Atomic absorption spectroscopy:-Quantitative, for concentrations of metal ions-Light source: Cathode lamp-Wavelength of light source is ion-specific, based on what metals concentration is being analysed-Electron excitation event-A cathode lamp of corresponding metal to be tested releases light of certain frequencies unique to the metal. The absorption of these particular wavelengths by the sample will depend on the concentration of the metal in question.-Graph: Calibration curve (absorbance at fixed wavelength, over concentration) UV/Visible spectroscopy:-Quantitative, for concentrations of organic and inorganic molecules-Light source: Filament-Wavelength of light source is initially varied to find maximum absorption wavelength of a sample of known concentration (compared to a reference solution without the sample). From then on the same light frequency can be used to test the concentration of the same sample in a different solution based on its relative absorption to the first sample.-Electron excitation event-Graph: Calibration curve (absorbance at fixed wavelength, over concentration) Infrared spectroscopy:-Generally qualitative, for what bonds in organic compounds are present-Molecules absorb energy from infrared electromagnetic waves within bonds. The bonds will release this energy as scattered infrared waves. The amount of infrared radiation of certain wavelength that a bond absorbs can be determined by a detector.-Graph: Infrared absorption spectrum

Nuclear magnetic resonance spectroscopy (1H and 13C):-Generally qualitative, for carbon/hydrogen skeleton information-Radio waves of certain frequency are directed towards an organic compound, within a magnetic field. Carbon 13 or Hydrogen nuclei have intrinsic magnetic spin that align with the field and produce a net magnetic field. Radio waves of certain frequency will disrupt this magnetic field strength produced by these C or H atoms by magnetic resonance, which is detected. The frequency will depend on the atoms bonding environment.-Graph: NMR spectrum-Split peaks rule: A hydrogen signal will have n + 1 small peaks, where n is the number of hydrogens on adjacent carbons. Mass spectroscopy:-Generally qualitative, for structural information (not in VCE) and molar mass (in VCE)-Vaporised and ionised sample is passed through electric and magnetic field. A detector measures mass per charge based on extent of deflection due to the magnetic field-Graph: Mass spectrum (peak intensity over m/z)-Molecular ion (M+) produces peak with greatest mass/charge ratio-Base peak: highest peak CHROMATOGRAPHYChromatography: The set of chemical analyses involving mobile and stationary phase adsorption and desorption. Usually involves separation of chemicals. The retention time/retention factor depends on:-Molecule size-Polarity of molecule, and polarity of mobile and stationary phase Paper/Thin layer chromatography:-Generally qualitative, for presence of substances. However concentrations can be found based on dot colouration intensities-Stationary phase is paper/thin layer material-Mobile phase is liquid solvent-Retention factor:

Gas chromatography:-Quantitative, for concentrations of easily vaporised molecules-Stationary phase is solid/waxy-Mobile phase is gas-Graph: Chromatogram (sample intensity over retention time) High performance liquid chromatography:-Quantitative, for large/thermally unstable molecules-Stationary phase is solid/waxy-Mobile phase is liquid-Graph: Chromatogram (sample intensity over retention time) For GC and HPLC:-The bigger the molecule is the longer the retention time-The finer the stationary phase is the longer the retention times (smaller spacing on average)-Total amount/concentration can be determined from relative area under peaks on chromatogram THERMODYNAMICS: The change in enthalpy or bond energy of a reaction. Typically directly relates to a heat transfer. Negative : exothermicPositive : endothermic is typically given in kJ/mol. This does NOT necessarily signify per mole of a substance, but rather per molar quantities as given in the equation. However, c (heat of combustion) is always given in kJ, per mole of fuel. (some proportional equations will have half quantities of O2) Hesss Law: f: The enthalpy of formation of one mole of a substance from its substituent elements in standard state. Calorimetry:Calorimeters need to be calibrated to account for heat loss from the system to the surroundings. -. This is akin to the heat capacity of the calorimeter. The energy delivered is through either:-The ignition of a fuel of known heat of combustion and amount-Passing a known current (with known voltage) through a heating element for a certain time - where is the specific heat capacity of a substance (in Jg-1K-1). If a process if x% efficient, then x% of the theoretical yield of products is formed. REACTION RATES AND EQUILIBRIUM

Reaction quotient: Equilibrium position: The current proportion of reactants and products. Directly related to Q (reaction quotient). Be very careful with terminology here! The equilibrium position of an unhindered system will naturally approach equilibrium state. At equilibrium, the rates of forward and backward reaction are equal. Also, (equilibrium constant). When system is not at equilibrium, the equilibrium position will shift such that Q approaches Kc. If the forward reaction is favoured, Q will increase to Kc.If the backward reaction is favoured, Q will decrease to Kc. The units to Kcare given by dimensional analysis of the reaction quotient. Le Chateliers Principle: A change in an equilibrium system will cause a partial opposition to this change. -Volume change immediately affects Q and a partial opposition to this volume change is predicted-Adding reactant immediately affects amount of reactant and Q and a partial opposition to this concentration change is predicted-Temperature change immediately affects Kc and a partial opposition to this temperature change is predicted-Adding a catalyst increases the forward and backward rates proportionally, increasing the speed at which equilibrium is achieved but not changing equilibrium position nor point of equilibrium. Neither Q nor Kc change as an immediate result of this. For pressure arguments that allow volume change use the following statement: Increased/decreased pressure will favour the reaction that produces fewer/greater gas molecules (respectively) LCP may not predict what happens with changes caused by pressure at constant volume.Eg. -Adding inert gas at constant volume-Heating gases at constant volume Kc will only change as temperature changes. Consider an increased or decreased temperature as an increased or decreased supply of heat, and apply LCP. Exothermic equilibrium reactionEndothermic equilibrium reaction

Increased tempFavours backward endothermic reaction (using excess heat), using products and producing reactants. Kc decreases, so Q will decrease to the new Kc.Favours forward endothermic reaction (using excess heat), using reactants and producing products. Kc increases, so Q will increase to the new Kc.

Decreased tempFavours forward exothermic reaction (making missing heat), using reactants and producing products. Kc increases, so Q will increase to the new Kc.Favours backward exothermic reaction (making missing heat), using products and producing reactants. Kc decreases, so Q will decrease to the new Kc.

Self-ionisation of water is endothermic and therefore by equilibrium principles will favour dissociation into ions as temperature increases. If a weak acid is diluted, the H+ concentration will decrease, but the percentage ionisation of the acid will increase. This is because water is added to the system which shifts the following dissociation reaction in the forward direction:

(likewise for weak bases)The amount of ions will increase but because this is only a partial increase, the increased volume gives an overall concentration decrease. ELECTROCHEMISTRYCathode: Reduction siteAnode: Oxidation siteElectrons always flow from anode to cathode Reaction is spontaneous if: Eoxidant > Ereductant Galvanic cells (spontaneous):-Chemical energy electrical energy-Positive electrode becomes cathode-Negative electrode becomes anode A fuel cell is a galvanic cell that requires a continuous supply of the reactants.Eg. H2/O2 fuel cell Electrolytic cells (require electrical voltage source):-Electrical energy chemical energy-Positive electrode becomes anode-Negative electrode becomes cathode Salt bridge: contains soluble, unreactive ionic compound to balance charge buildups, allowing circuit to function over time until depletion

In electrolysis, the strongest oxidant and reductant present will react.It is given that Estrongest reductant > Estrongest oxidant as the reaction is not spontaneous. In electrolysis, always check if water will electrolyse first at either electrode. For example, NaCl cannot be electrolysed to form Na and Cl in water, but must be heated to molten form for the reaction to work. Recharging requires:-Positive terminal to negative electrode-Negative terminal to positive electrode-Supplied voltage must be greater in magnitude than cell discharge voltage For a rechargeable battery to work:-The products of discharge must maintain electrical contact with the respective electrodes.-The products of discharge must be the strongest oxidants/reductants during recharge. Electrochemical series limitations:-Does not predict reaction rateEg. H2O2 reacting with itself-Oxide coatings may stall reaction completelyEg. Al2O3 on Al-Only applies for standard conditions (1M concentrations, SLC)Eg. If Cl- is in high concentration, Cl- can be oxidised in preference of H2O Energy produced by a (galvanic) cell:

V is voltageI is currentQ is amount of electrons (in coulombs)n(e-) is amount of electrons (in mol)F is Faradays constant (96500 C mol-1) FUELS (this section needs more work)A renewable energy source can be replenished at the rate of consumption.A carbon neutral fuel does not increase the net amount of carbon emissions in the atmosphere upon consumption.Fossil fuels are formed from the degradation of animal and plant matter over millions of years. Non-renewable fuels:Petroleum-Crude oil consisting of many different hydrocarbons, found underground, formed from marine organisms-Can be treated with cracking and fractional distillation to separate hydrocarbons and make them more useful fuels Coal-Found underground, formed from plant matter-Burning produces carbon dioxide and sulfur dioxide not carbon neutral Natural gas (CH4)-A plentiful resource, formed from marine organisms huge underground reservoirs-However, there are environment impacts associated with leaking of the gas during collection methane is a far more potent greenhouse gas than carbon dioxide-Combustion of natural gas will produce carbon dioxide not carbon neutral Renewable fuels:Biodiesel-Typically esters formed from fatty acids (extracted from animal fat)-Standard fatty (carboxylic) acid + alcohol reaction with acid to produce biodiesel-Combustion of biodiesel will produce carbon dioxide not carbon neutral Hydrogen/oxygen fuel cell-Produces only water as a byproduct-However, carbon based emissions made still be a problem in the production of H2-Expensive, difficult to store and transport fuels Nuclear fuels (for use in nuclear fission) Hydrogen (for use in nuclear fusion)-Predicted to be the most energy dense fuel far more than any commonly used fuels

MISCELLANEOUS:-Standardisation: determination of concentration by titration-Standard solution: solution with accurately known concentration often prepared using a primary standard (titre)Primary standard properties:1. Solid crystalline substance2. Large molar mass3. Stable (not reactive with air)4. Available NaOH NOT primary standard due to reaction with CO2Na2CO3 is a primary standard for acid/baseOxalic acid is a primary standard for redox Solubility rules:-All group 1 compounds-All NH4+ compounds-All nitrate (NO3-), chlorate (ClO3-), perchlorate (ClO4-), and acetate (CH3COO-) salts-All chlorides except for Ag+, Hg2+, Pb2+-All sulfates except for Ba2+, Sr2+, (Pb2+, Ca2+, Ag+ moderately)-No hydroxides except Ba2+, Sr2+, Pb2+ (or group 1 or NH4+)-No carbonates (unless group 1 or NH4+)http://www.chem.sc.edu/faculty/morgan/resources/solubility/

Tips:SPANACompounds containing Sodium, Potassium, Ammonium, Nitrate and Acetate ions are always soluble in water.CHOPSCompounds containing Carbonate, Hydroxide, Oxide, Phosphate and Sulfide ions are generally water insoluble unless combined with SPANA ions