Chemical reactions
Chemistry · Unit 1 — Chemical fundamentals — structure, properties and reactions · Chemical reactions — reactants, products and energy change
Learning objectives (25)
LO-1Analyse data for heat of combustion, heat of neutralisation and reactions in aqueous solutions to determine heat, mass, specific heat capacity, temperature and enthalpy change. Chem istry 2025 v1.3 Mole concept and law of conservation of massLO-2Analyse data to determine percentage and theoretical yield. (Formula: percentage yield (%) = experimental yield theoretical yield × 100 1)LO-3Analyse enthalpy level diagrams and thermochemical equations to determine the relative stabilities of reactants and products, and the sign of the enthalpy change (ΔH) for a reaction.LO-4Apply the mole concept to calculate the mass of reactants and products; amount of substance in moles; number of representative particles; and molar mass of atoms, ions, molecules and formula units. (Formula: moles (𝑛) = mass (m) molar mass (M))LO-5Calculate the enthalpy change (ΔH) for a reaction given temperature changes, quantities of reactants and mass of water. (Formula: ΔH = H(products) – H(reactants))LO-6Calculate the heat change (Q) for a substance given the mass, specific heat capacity and temperature change. (Formula: Q = mcΔT)LO-7Determine balanced chemical equations, including state symbols (s), (l), (g) and (aq), for a variety of reactions, e.g. single displacement, double-displacement, acid-base, combustion, combination, decomposition and simple redox reactions. Exothermic and endothermic reactionsLO-8Determine limiting reactants.LO-9Determine the percentage composition from relative atomic masses; empirical formula of a compound from the percentage composition by mass; and molecular formula of a compound from its empirical formula and molar mass.LO-10Discriminate between exothermic and endothermic reactions.LO-11Discriminate between experimental and theoretical yield.LO-12Evaluate fuels, including fossil fuels and biofuels, in terms of their energy output, their suitability for purpose, and the nature of products of combustion. Investigate:LO-13Explain how endothermic and exothermic reactions relate to the law of conservation of energy and the breaking and reforming of bonds.LO-14Explain that the mole concept relates mass, moles and molar mass.LO-15Explain, in terms of average bond enthalpies, why reactions are exothermic or endothermic.LO-16Identify that chemical reactions and phase changes involve energy changes, commonly observable as changes in the temperature of the surroundings and/or the emission of light.LO-17Identify the limitations of using average bond enthalpies to calculate enthalpy change.LO-18limiting reagent/s and percentage yieldLO-19Sketch enthalpy level diagrams for exothermic and endothermic reactions.LO-20State that a mole is a precisely defined quantity of matter equal to Avogadro’s number of particles.LO-21State that heat is a form of energy, and that temperature is a measure of the average kinetic energy of the particles.LO-22State the law of conservation of mass.LO-23the empirical formula of a compound from reactions involving mass changeLO-24the enthalpy change of a reaction, e.g. calorimetry or Hess’s Law.LO-25types of chemical reactions
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