ASRJC 2024 H2 Chem Thermochemistry Notes

2024 JC1 H2 CHEMICAL ENERGETICS I (THERMOCHEMISTRY) 2024/ASRJC/Chemistry 1 Anderson Serangoon Junior College H2 Chemistry CHEMICAL ENERGETICS I (THERMOCHEMISTRY) Contents/Outline 1 Introducing enthalpy change, exothermic and endothermic reactions 2 Defining common enthalpy changes: ∆ H of reaction, formation, combustion, neutralisation, atomisation and bond energy 3 Determining enthalpy changes using experiments and q = mcT 4 Defining enthalpy changes involving ionic compounds: ∆ H of ionisation, electron affinity, lattice energy, hydration and solution 5 Determining enthalpy changes by applying Hess’ Law through energy cycle (including Born −Haber cycles), formulae and algebraic manipulation. Learning Outcomes Students should be able to: (a) explain that some chemical reactions are accompanied by energy changes, principally in the form of heat energy; the energy changes can be exothermic (∆H negative) or endothermic (∆H positive) (b) construct and interpret a reaction pathway diagram, in terms of the enthalpy change of the reaction and of the activation energy (c) explain and use the terms: (i) enthalpy change of reaction and standard conditions , with particular reference to: formation; combustion; hydration; solution; neutralisation; atomisation (ii) bond energy (∆H positive, i.e. bond breaking) (iii) lattice energy (∆H negative, i.e. gaseous ions to solid lattice) (d) calculate enthalpy changes from appropriate experimental results, including the use of the relationship heat change = mc∆T (e) explain, in qualitative terms, the effect of ionic charge and of ionic radius on the numerical magnitude of a lattice energy (f) apply Hess’ Law to construct simple energy cycles, e.g. Born−Haber cycle, and carry out calculations involving such cycles and relevant energy terms (including ionisation energy and electron affinity), with particular reference to: (i) determining enthalpy changes that cannot be found by direct experiment, e.g. enthalpy change of formation from enthalpy changes of combustion (ii) the formation of a simple ionic solid and of its aqueous solution (iii) average bond energies References 1. Chemistry for Advanced Level, Cann and Hughes, Murray 2. Understanding Advanced Physical Inorganic Chemisry, Jeanne Tan and Chan Kim Seng, WS education 3. Chemistry, The Molecular Nature of Matter and Change (Fourth Edition), Silberberg, McGraw Hill 4. Chemistry & Chemical Reactivity (Sixth Edition), Kotz, Treichel and Weaver, Thomson 5. Chemistry The Central Science (Ninth Edition), Brown, LeMay, Bursten, Prentice Hall

2024 JC1 H2 CHEMICAL ENERGETICS I (THERMOCHEMISTRY) 2024/ASRJC/Chemistry 2 Contents: Part 1: Introduction 1.1 System and surroundings 1.2 Heat transfer 1.3 Enthalpy and enthalpy change 1.4 Exothermic and endothermic reactions 1.5 Standard conditions and standard states Part 2: Types of enthalpy changes 2.1 Standard