Chemistry Form 6 Notes
Chemistry Form 6 Complete Notes Devine Vision Chemistry Form 6 complete notes post 00Overview 01Chemical Kinetics 02Redox Stoichiometry and Iodometric Titration 03Electrode Potential, Conductivity and Kohlrausch’s Law 04Amines 05Chemical Equilibrium: Kc, Kp and Temperature Effects 06Coordination Chemistry and Transition Metals 07Soil Chemistry: Cation Exchange, Soil Acidity, Liming and Fertilizers 08Solubility Product, Precipitation and Qualitative Analysis 09Environmental Chemistry and Pollution 10Formula and Reaction Centre 11Question and Example Bank 12Full Source Transcript Clean HTML post with no JavaScript. Equations and questions are shown as readable text boxes. Source pages are included at the end so no educational concept is intentionally omitted. Open chapter navigation 00Overview 01Chemical Kinetics 02Redox Stoichiometry and Iodometric Titration 03Electrode Potential, Conductivity and Kohlrausch’s Law 04Amines 05Chemical Equilibrium: Kc, Kp and Temperature Effects 06Coordination Chemistry and Transition Metals 07Soil Chemistry: Cation Exchange, Soil Acidity, Liming and Fertilizers 08Solubility Product, Precipitation and Qualitative Analysis 09Environmental Chemistry and Pollution 10Formula and Reaction Centre 11Question and Example Bank 12Full Source Transcript Advanced Level Chemistry Chemistry Form 6 Complete Notes This post organizes the uploaded Chemistry Form 6 document into readable chapters, clear formula boxes, reaction boxes, examples, question areas and a full page-by-page source transcript. On a phone, use the chapter navigation at the top to jump directly to any topic. Formula boxes, source transcripts and wide tables can be scrolled sideways when needed. Physical ChemistryOrganic ChemistryInorganic ChemistrySoil & Environmental ChemistryNo Script 01 Chemical Kinetics Chemical kinetics is the study of the speed or rate of a chemical reaction under different conditions and the mechanism of the reaction. Rate of reaction: the change in concentration of reactants or products per unit time. For: A + 3B → 2C + 2D Rate of reaction = – rate of disappearance of A Rate of reaction = – 1/3 × rate of disappearance of B Rate of reaction = 1/2 × rate of formation of C Rate of reaction = 1/2 × rate of formation of D Rates of disappearance are negative because concentration decreases with time. Rates of formation are positive because concentration increases with time. To remove the effect of stoichiometry, the rate for each species is divided by the coefficient of that species in the balanced equation. Example from the notes: rate from concentration change Initial concentration of A = 1.0 M. After one minute concentration of A = 0.9982 M. Rate of reaction = -Δ[A] / Δt = – (0.9982 – 1.0) M / 60 s = 3 × 10^-5 mol L^-1 s^-1 For C in A + 3B → 2C + 2D: Rate of reaction = 1/2 × rate of formation of C Rate of formation of C = 2 × rate = 6 × 10^-5 mol L^-1 s^-1 Rate Law The rate law states that the rate of reaction is directly proportional to the concentration of the reactants, each raised to a power equal to the order of reaction. Rate ∝ [Reactants] Rate = K[Reactants] For A + 2B → Products: Rate = K[A]^a[B]^b K is the rate constant or velocity constant. The order with respect to A is a. The order with respect to B is b. The overall order is a + b, and it may be fractional. Order of reaction is obtained experimentally, not from the overall balanced equation. Zero Order and First Order Reactions Zero order The rate is independent of the concentration of the reactant. A → Products Rate = K[A]^0 Rate = K Unit of K = mol L^-1 s^-1 First order The rate is directly proportional to the first power of the concentration of a single reactant. A → Products Rate = K[A]^1 Rate = K[A] Unit of K = s^-1 or time^-1 02 Redox Stoichiometry and Iodometric Titration The notes include redox mole-ratio calculations involving permanganate, dichromate and iodate oxidants. Iodine produced is titrated with sodium thiosulphate until pale yellow, then starch is added and titration continues until the blue-black colour is discharged. Important note: starch is not added at the beginning because iodine concentration is large. Iodine reacts with starch to form a blue-black complex, causing more sodium thiosulphate to be required to discharge the colour. Acidified permanganate reaction: 2MnO4^- + 10I^- + 16H^+ → 2Mn^2+ + 5I2 + 8H2O Iodine with thiosulphate: 2S2O3^2- + I2 → S4O6^2- + 2I^- Mole ratio from the notes: MnO4^- : S2O3^2- = 1 : 5 Acidified dichromate reaction: Cr2O7^2- + 14H^+ + 6e^- → 2Cr^3+ + 7H2O 2I^- → I2 + 2e^- Combined mole ratio from the notes: Cr2O7^2- : S2O3^2- = 1 : 6 Acidified iodate reaction: IO3^- + I^- + H^+ produces I2 The mole ratio from the notes: IO3^- : S2O3^2- = 1 : 6 03 Electrode Potential, Conductivity and Kohlrausch’s Law Electrode Potential Metals have a small tendency to dissolve in a solution of their ions, producing cations and leaving valency electrons on the metal rod. The metal acquires a negative potential which prevents further release of cations and an equilibrium is established. M ⇌ M^n+ + ne^- The region of solution close to the rod becomes positively charged while the rod carries a layer of negative charge. This forms an electric double layer known as the Helmholtz double layer. The voltage between the electrode and surrounding solution is called electrode potential. Kohlrausch’s Law of Independent Ionic Mobility Kohlrausch’s law states that the molar conductivity of an electrolyte at infinite dilution is equal to the sum of the molar conductivities of the cation and anion. Λ∞(electrolyte) = λ∞(cation) + λ∞(anion) Example relationships from the notes: Λ∞(NaCl) = λ∞(Na+) + λ∞(Cl-) Λ∞(Al2(SO4)3) = 2λ∞(Al3+) + 3λ∞(SO4^2-) For weak electrolytes, the molar conductivity at infinite dilution can be calculated using strong electrolytes. The notes use ethanoic acid with potassium ethanoate, hydrochloric acid and potassium chloride. CH3COOH + KCl → CH3COOK + HCl Λ∞(CH3COOH) = Λ∞(CH3COOK) + Λ∞(HCl) – Λ∞(KCl) 04 Amines Amines are derivatives of ammonia in which one or more hydrogen atoms have been replaced by an alkyl group or aryl group. Primary amine R—NH2 Secondary amine R—NH—R Tertiary

