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Pearson Edexcel IAL Chemistry

Unit 4: Rates, Equilibria and Further Organic Chemistry

Topic 11: Kinetics

Topic 12: Entropy and Energetics

12.1—That, since endothermic reactions can occur spontaneously at room temperature, enthalpy changes alone do not control whether

12.2—Entropy as a measure of disorder of a system in terms of the random dispersal of molecules and of energy quanta between

12.3—The entropy of a substance increases with temperature, that entropy increases as solid → liquid → gas and that perfect

12.4—Interpret the natural direction of change as being in the direction of increasing total entropy (positive entropy change)

12.5—Why entropy changes occur during: i changes of state ii dissolving of a solid ionic lattice iii reactions in which there is

12.6—The total entropy change of any reaction is the sum of the entropy change of the system and the entropy change of

12.7—The entropy change of the system for a reaction, ∆Ssystem, given the entropies of the reactants and products

12.8—The entropy change in the surroundings, and hence ∆Stotal

12.9—The feasibility of a reaction depends on: i the balance between ∆Ssystem and ∆Ssurroundings, so that even endothermic

12.10—Reactions can occur as long as ∆Stotal is positive even if one of the other entropy changes is negative

12.11—And distinguish between the concepts of thermodynamic stability and kinetic stability

12.12—Define the terms: i standard enthalpy change of atomisation, ∆atH ii electron affinity iii lattice energy (as the exothermic

12.13—Construct Born-Haber cycles and carry out related calculations

12.14—A comparison of the experimental lattice energy value (from a Born-Haber cycle) with the theoretical value (obtained

12.15—Polarisation of anions by cations leads to some covalency in an ionic bond, based on evidence from the Born-Haber cycle

12.16—Define the terms ‘enthalpy change of solution, ∆solH’ and ‘enthalpy change of hydration, ∆hydH of an ion’

12.17—Energy cycles and energy level diagrams to calculate the enthalpy change of solution of an ionic compound

12.18—The effect of ionic charge and ionic radius on the values of enthalpy change of hydration and the lattice energy of an ionic

12.19—Entropy and enthalpy changes of solution values to predict the solubility of ionic compounds and discuss trends in

Topic 13: Chemical Equilibria

Topic 14: Acid-base Equilibria

Topic 15: Organic Chemistry: Carbonyls, Carboxylic Acids and Chirality

Unit 5: Transition Metals and Organic Nitrogen Chemistry

Unit 6: Practical Skills in Chemistry II

Assessed mathematical skills and measurement conventions

A-Level/Edexcel/Chemistry//A2/Concept/Unit 4: Rates, Equilibria and Further Organic Chemistry/Topic 12: Entropy and Energetics/12.3—The entropy of a substance increases with temperature, that entropy increases as solid → liquid → gas and that perfect

Unit 4: Rates, Equilibria and Further Organic Chemistry A2

Syllabus: 2017
Section: —
Level: A2

Exam analysis

Most tested topics

Topic 11: Kinetics
Topic 12: Entropy and Energetics
Topic 13: Chemical Equilibria
Topic 14: Acid-base Equilibria
Topic 15: Organic Chemistry: Carbonyls, Carboxylic Acids and Chirality