{"id":12516,"date":"2026-10-03T08:33:57","date_gmt":"2026-10-03T07:33:57","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/"},"modified":"2026-10-03T08:37:17","modified_gmt":"2026-10-03T07:37:17","slug":"topic-23-chemical-energetics","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/","title":{"rendered":"Topic 23 Chemical Energetics"},"content":{"rendered":"\n<div class=\"ols-cie23-page\">\n\n  <aside class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>A Level Chemistry<\/p>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Topic 23 Chemical Energetics<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/\">Topic 23 Chemical Energetics Overview<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/lattice-energy-and-born-haber-cycles\/\">Lattice Energy and Born\u2013Haber Cycles<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/lattice-energy-trends-and-covalent-character\/\">Lattice Energy Trends and Covalent Character<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/enthalpy-of-solution-and-hydration\/\">Enthalpy of Solution and Hydration<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/entropy-and-the-direction-of-change\/\">Entropy and the Direction of Change<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/calculating-entropy-changes\/\">Calculating Entropy Changes<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/feasibility-gibbs-energy-and-temperature\/\">Feasibility, Gibbs Energy and Temperature<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/thermodynamic-and-kinetic-stability\/\">Thermodynamic and Kinetic Stability<\/a>\n      <\/li>\n    <\/ul>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Other Sections<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-5-chemical-energetics\/\">Topic 5 Chemical Energetics (AS)<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-26-reaction-kinetics\/\">Topic 26 Reaction Kinetics<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-10-group-2\/\">Topic 10 Group 2<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/practical-skills\/\">Practical Skills<\/a>\n      <\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\n\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      .split('#')[0]\r\n      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#34d399 45%, #047857 100%); }\n    .ols-cie23-visual--ho { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #fefce8 0%, #facc15 45%, #a16207 100%); }\n    .ols-cie23-visual--cd { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #f0fdf4 0%, #86efac 45%, #166534 100%); }\n    .ols-cie23-visual--hi { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #fdf4ff 0%, #d8b4fe 45%, #7e22ce 100%); }\n    .ols-cie23-visual--ca { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #fff7ed 0%, #fb923c 45%, #9a3412 100%); }\n    .ols-cie23-visual--de { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #eef2ff 0%, #818cf8 45%, #3730a3 100%); }\n    .ols-cie23-visual--lc { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #ecfeff 0%, #22d3ee 45%, #0e7490 100%); }\n    .ols-cie23-visual--ei { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #f5f3ff 0%, #a78bfa 45%, #5b21b6 100%); }\n    .ols-cie23-visual--kc { background: radial-gradient(circle at 24% 18%, rgba(255,255,255,0.46), transparent 24%), linear-gradient(135deg, #f0fdf4 0%, #4ade80 45%, #166534 100%); }\n  <\/style>\n\n  <!-- BREADCRUMB BAR -->\n  <div class=\"ols-cie23-breadcrumb-bar\">\n    <div class=\"ols-cie23-container\">\n      <nav class=\"ols-cie23-breadcrumb\" aria-label=\"Breadcrumb\">\n          <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n          <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n          <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/\">Cambridge International (CIE)<\/a> \/\n          <span>Topic 23 Chemical Energetics<\/span>\n        <\/nav>\n    <\/div>\n  <\/div>\n\n  <!-- INTRO -->\n  <section class=\"ols-cie23-intro\">\n    <div class=\"ols-cie23-container\">\n      <div class=\"ols-cie23-intro-inner\">\n        <div>\n          <div class=\"ols-cie23-eyebrow\">Cambridge International AS &amp; A Level Chemistry &#8211; Physical Chemistry (A Level)<\/div>\n          <h1>Topic 23<br>Chemical<br>Energetics<\/h1>\n          <div class=\"ols-cie23-accent-bar\"><\/div>\n          <p class=\"ols-cie23-intro-lead\">Topic 23 covers lattice energy and the enthalpy change of atomisation, first electron affinity and its trends in Groups 16 and 17, Born\u2013Haber cycles with calculations, the effect of ionic charge and radius on lattice energy, enthalpies of hydration and solution with energy cycles, entropy as the number of arrangements of particles and energy, the sign of entropy changes for changes of state, temperature and gas molecules, \u0394S from standard entropies, and the Gibbs equation \u0394G\u29b5 = \u0394H\u29b5 \u2212 T\u0394S\u29b5 with feasibility and the effect of temperature.<\/p>\n        <\/div>\n        <div class=\"ols-cie23-info-grid\">\n          <div class=\"ols-cie23-info-card\"><div class=\"ols-cie23-info-card-label\">Exam Paper<\/div><div class=\"ols-cie23-info-card-value\">Paper 4<\/div><div class=\"ols-cie23-info-card-sub\">9701 A Level<\/div><\/div>\n          <div class=\"ols-cie23-info-card\"><div class=\"ols-cie23-info-card-label\">Learning Outcomes<\/div><div class=\"ols-cie23-info-card-value\">23.1 &#8211; 23.4<\/div><div class=\"ols-cie23-info-card-sub\">4 sections covered<\/div><\/div>\n          <div class=\"ols-cie23-info-card\"><div class=\"ols-cie23-info-card-label\">Topic Parts<\/div><div class=\"ols-cie23-info-card-value\">7 pages<\/div><div class=\"ols-cie23-info-card-sub\">Revision notes available<\/div><\/div>\n          <div class=\"ols-cie23-info-card\"><div class=\"ols-cie23-info-card-label\">Exam Board<\/div><div class=\"ols-cie23-info-card-value\">Cambridge<\/div><div class=\"ols-cie23-info-card-sub\">9701 (2025 onwards)<\/div><\/div>\n        <\/div>\n      <\/div>\n    <\/div>\n  <\/section>\n\n  <!-- TOPIC CARDS -->\n  <section class=\"ols-cie23-topics\">\n    <div class=\"ols-cie23-container\">\n      <div class=\"ols-cie23-section-header\">\n        <h2 class=\"ols-cie23-section-title\">Revision Notes<\/h2>\n        <p class=\"ols-cie23-section-sub\">Work through Topic 23 Chemical Energetics in a structured sequence.<\/p>\n      <\/div>\n      <div class=\"ols-cie23-cards-grid\">\n\n        <!-- Card 1: w => `${lattC(w)} and Born\u2013Haber Cycles` -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/lattice-energy-and-born-haber-cycles\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--de\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">Hess\u2019s law for ionic solids<\/div>\n                <div class=\"ols-cie23-visual-main\">Born\u2013Haber<br>Cycles<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>lattice energy, \u0394atH, electron affinity<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">1<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Lattice Energy and Born\u2013Haber Cycles<\/p>\n            <p class=\"ols-cie23-card-desc\">Lattice energy and Born\u2013Haber cycles: definitions of atomisation, ionisation energy and electron affinity, constructing the cycle for NaCl and MgCl\u2082 and calculating the missing value.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 2: w => `${lattC(w)} Trends and Covalent Character` -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/lattice-energy-trends-and-covalent-character\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--lc\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">Charge density<\/div>\n                <div class=\"ols-cie23-visual-main\">Polarisation and<br>Covalent Character<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>theoretical against experimental<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">2<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Lattice Energy Trends and Covalent Character<\/p>\n            <p class=\"ols-cie23-card-desc\">Lattice energy trends: charge and radius, the perfect ionic model against Born\u2013Haber values, polarisation and covalent character in ionic compounds.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 3: Enthalpy of Solution and Hydration -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/enthalpy-of-solution-and-hydration\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--ei\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">Lattice broken, ions hydrated<\/div>\n                <div class=\"ols-cie23-visual-main\">Solution and<br>Hydration<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>\u0394solH = \u2212LE + \u03a3\u0394hydH<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">3<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Enthalpy of Solution and Hydration<\/p>\n            <p class=\"ols-cie23-card-desc\">Enthalpy of solution and hydration: definitions, energy cycles with lattice energy, worked calculations and the effect of ionic charge and radius.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 4: Entropy and the Direction of Change -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/entropy-and-the-direction-of-change\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--ox\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">Disorder and dispersal<\/div>\n                <div class=\"ols-cie23-visual-main\">Entropy<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>S rises: solid, liquid, gas<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">4<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Entropy and the Direction of Change<\/p>\n            <p class=\"ols-cie23-card-desc\">Entropy: disorder and the dispersal of energy, entropy and temperature, changes of state, dissolving, gas moles and the natural direction of change.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 5: Calculating Entropy Changes -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/calculating-entropy-changes\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--tc\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">\u03a3S(products) \u2212 \u03a3S(reactants)<\/div>\n                <div class=\"ols-cie23-visual-main\">Entropy<br>Calculations<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>J K\u207b\u00b9 mol\u207b\u00b9, sign and size<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">5<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Calculating Entropy Changes<\/p>\n            <p class=\"ols-cie23-card-desc\">Entropy calculations: \u0394S from standard entropies, units and worked examples.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 6: Feasibility, Gibbs Energy and Temperature -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/feasibility-gibbs-energy-and-temperature\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--tr\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">\u0394G = \u0394H \u2212 T\u0394S<\/div>\n                <div class=\"ols-cie23-visual-main\">Feasibility and<br>Temperature<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>T = \u0394H \u00f7 \u0394S<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">6<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Feasibility, Gibbs Energy and Temperature<\/p>\n            <p class=\"ols-cie23-card-desc\">Feasibility: \u0394G = \u0394H \u2212 T\u0394S, the sign of \u0394G, the effect of temperature and the temperature at which a reaction becomes feasible.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 7: Thermodynamic and Kinetic Stability -->\n        <a class=\"ols-cie23-card ols-cie23-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/thermodynamic-and-kinetic-stability\/\">\n          <div class=\"ols-cie23-card-img-wrap\">\n            <div class=\"ols-cie23-visual ols-cie23-visual--ca\">\n              <div class=\"ols-cie23-visual-panel\">\n                <div class=\"ols-cie23-visual-kicker\">Feasible is not fast<\/div>\n                <div class=\"ols-cie23-visual-main\">Thermodynamic and<br>Kinetic Stability<\/div>\n                <div class=\"ols-cie23-config-line\" aria-hidden=\"true\"><span>\u0394G, E\u2090, diamond and petrol<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-cie23-card-num\">7<\/div>\n            <span class=\"ols-cie23-card-status ols-cie23-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-cie23-card-body\">\n            <p class=\"ols-cie23-card-title\">Thermodynamic and Kinetic Stability<\/p>\n            <p class=\"ols-cie23-card-desc\">Thermodynamic and kinetic stability: feasible but slow reactions, activation energy and the limits of \u0394G and \u0394Stotal predictions.<\/p>\n            <span class=\"ols-cie23-card-cta\">Start revising<svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg><\/span>\n          <\/div>\n        <\/a>\n\n      <\/div>\n    <\/div>\n  <\/section>\n\n  <!-- SPECIFICATION -->\n  <section class=\"ols-cie23-spec-section\">\n    <div class=\"ols-cie23-container\">\n      <div class=\"ols-cie23-spec-wrap\">\n        <div class=\"ols-cie23-spec-pill\">Specification Coverage<\/div>\n        <h2 class=\"ols-cie23-spec-heading\">Topic 23 Chemical Energetics &#8211; Cambridge International A Level Chemistry<\/h2>\n        <p class=\"ols-cie23-spec-intro-text\">The following Cambridge learning outcomes state what candidates should be able to do. Wording is taken from the Cambridge International AS &amp; A Level Chemistry (9701) syllabus.<\/p>\n        <h3 class=\"ols-cie23-spec-group-title\">23.1 Lattice energy and Born\u2013Haber cycles<\/h3>\n        <div class=\"ols-cie23-spec-rows\">\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.1.1<\/div><div class=\"ols-cie23-spec-text\"><div class=\"ols-cie23-spec-sub-list\"><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(a)<\/div><div class=\"ols-cie23-spec-sub-text\">define and use the term enthalpy change of atomisation, \u0394Hat<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(b)<\/div><div class=\"ols-cie23-spec-sub-text\">define and use the term lattice energy, \u0394Hlatt (the change from gas phase ions to solid lattice)<\/div><\/div><\/div><\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.1.2<\/div><div class=\"ols-cie23-spec-text\"><div class=\"ols-cie23-spec-sub-list\"><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(a)<\/div><div class=\"ols-cie23-spec-sub-text\">define and use the term first electron affinity, EA<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(b)<\/div><div class=\"ols-cie23-spec-sub-text\">explain the factors affecting the electron affinities of elements<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(c)-i<\/div><div class=\"ols-cie23-spec-sub-text\">describe and explain the trends in the electron affinities of the Group 16 elements<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(c)-ii<\/div><div class=\"ols-cie23-spec-sub-text\">describe and explain the trends in the electron affinities of the Group 17 elements<\/div><\/div><\/div><\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.1.3<\/div><div class=\"ols-cie23-spec-text\">construct and use Born\u2013Haber cycles for ionic solids (limited to +1 and +2 cations, \u20131 and \u20132 anions)<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.1.4<\/div><div class=\"ols-cie23-spec-text\">carry out calculations involving Born\u2013Haber cycles<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.1.5<\/div><div class=\"ols-cie23-spec-text\"><div class=\"ols-cie23-spec-sub-list\"><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">a<\/div><div class=\"ols-cie23-spec-sub-text\">explain, in qualitative terms, the effect of ionic charge on the numerical magnitude of a lattice energy<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">b<\/div><div class=\"ols-cie23-spec-sub-text\">explain, in qualitative terms, the effect of ionic radius on the numerical magnitude of a lattice energy<\/div><\/div><\/div><\/div><\/div>\n        <\/div>\n\n        <h3 class=\"ols-cie23-spec-group-title\">23.2 Enthalpies of solution and hydration<\/h3>\n        <div class=\"ols-cie23-spec-rows\">\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.2.1<\/div><div class=\"ols-cie23-spec-text\"><div class=\"ols-cie23-spec-sub-list\"><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">a<\/div><div class=\"ols-cie23-spec-sub-text\">define and use the term enthalpy change of hydration, \u0394Hhyd<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">b<\/div><div class=\"ols-cie23-spec-sub-text\">define and use the term enthalpy change of solution, \u0394Hsol<\/div><\/div><\/div><\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.2.2<\/div><div class=\"ols-cie23-spec-text\">construct and use an energy cycle involving enthalpy change of solution, lattice energy and enthalpy change of hydration<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.2.3<\/div><div class=\"ols-cie23-spec-text\">carry out calculations involving the energy cycles in 23.2.2<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.2.4<\/div><div class=\"ols-cie23-spec-text\"><div class=\"ols-cie23-spec-sub-list\"><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">a<\/div><div class=\"ols-cie23-spec-sub-text\">explain, in qualitative terms, the effect of ionic charge on the numerical magnitude of an enthalpy change of hydration<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">b<\/div><div class=\"ols-cie23-spec-sub-text\">explain, in qualitative terms, the effect of ionic radius on the numerical magnitude of an enthalpy change of hydration<\/div><\/div><\/div><\/div><\/div>\n        <\/div>\n\n        <h3 class=\"ols-cie23-spec-group-title\">23.3 Entropy change, \u0394S<\/h3>\n        <div class=\"ols-cie23-spec-rows\">\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.3.1<\/div><div class=\"ols-cie23-spec-text\">define the term entropy, S, as the number of possible arrangements of the particles and their energy in a given system<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.3.2<\/div><div class=\"ols-cie23-spec-text\"><div class=\"ols-cie23-spec-sub-list\"><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(a)<\/div><div class=\"ols-cie23-spec-sub-text\">predict and explain the sign of the entropy changes that occur during a change in state, e.g. melting, boiling and dissolving (and their reverse)<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(b)<\/div><div class=\"ols-cie23-spec-sub-text\">predict and explain the sign of the entropy changes that occur during a temperature change<\/div><\/div><div class=\"ols-cie23-spec-sub-row\"><div class=\"ols-cie23-spec-sub-code\">(c)<\/div><div class=\"ols-cie23-spec-sub-text\">predict and explain the sign of the entropy changes that occur during a reaction in which there is a change in the number of gaseous molecules<\/div><\/div><\/div><\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.3.3<\/div><div class=\"ols-cie23-spec-text\">calculate the entropy change for a reaction, \u0394S, given the standard entropies, S\u29b5, of the reactants and products, \u0394S\u29b5 = \u03a3S\u29b5(products) \u2212 \u03a3S\u29b5(reactants) (use of \u0394S = \u0394Ssurr + \u0394Ssys is not required)<\/div><\/div>\n        <\/div>\n\n        <h3 class=\"ols-cie23-spec-group-title\">23.4 Gibbs free energy change, \u0394G<\/h3>\n        <div class=\"ols-cie23-spec-rows\">\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.4.1<\/div><div class=\"ols-cie23-spec-text\">state and use the Gibbs equation \u0394G\u29b5 = \u0394H\u29b5 \u2212 T\u0394S\u29b5<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.4.2<\/div><div class=\"ols-cie23-spec-text\">perform calculations using the equation \u0394G\u29b5 = \u0394H\u29b5 \u2212 T\u0394S\u29b5<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--light\"><div class=\"ols-cie23-spec-code\">23.4.3<\/div><div class=\"ols-cie23-spec-text\">state whether a reaction or process will be feasible by using the sign of \u0394G\u29b5<\/div><\/div>\n          <div class=\"ols-cie23-spec-row ols-cie23-spec-row--mid\"><div class=\"ols-cie23-spec-code ols-cie23-spec-code--mid\">23.4.4<\/div><div class=\"ols-cie23-spec-text\">predict the effect of temperature change on the feasibility of a reaction, given standard enthalpy and entropy changes<\/div><\/div>\n        <\/div>\n      <\/div>\n    <\/div>\n  <\/section>\n\n<script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"CollectionPage\",\n      \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-23-chemical-energetics\/#webpage\",\n      \"url\": 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