Introduces the idea of one and two-step reactions 3 Distribution of stored 3.1.5.2 Maxwell–Boltzmann distribution 8.3 energy 8.4 Maxwell–Boltzmann distribution of molecular Explain the shape of different 8.5 energies in gases. Introduces the idea that energy diagrams, including –level frequency of collision is two-step reactions. Students should be able to draw and interpret proportional to square Draw the Maxwell-Boltzmann distribution curves for different root of the temperature. distribution of stored energy in temperatures. Introduces the gas molecules Boltzmann distribution Explain the shape of the curve of energy. 4 Determining rates of 3.1.5.3 Effect of temperature on reaction rate AT a, b, k and l 8.6 reaction Meaning of the term rate of reaction. PS 2.4 and 3.1: Recognise zero, first and second Students could Introduces the idea of order reactions from The qualitative effect of temperature changes investigate the zero, and second concentration-time graphs on the rate of reaction. Students should be effect of order with respect to interpret graphs of reactant able to use the Maxwell–Boltzmann temperature on different reactants. concentration or product distribution to explain why a small the rate of Investigation to calculate concentration against time temperature increase can lead to a large the order of a reaction calculate the rate of reaction by reaction of increase in rate. from concentration-time drawing tangents to the curve sodium graphs thiosulfate and hydrochloric acid 5 Initial rate method 8.6 by an initial rate method. describe how to find the initial Introduces the initial rate of reaction rate method and how it explain how to use the initial rate can be used to method to compare factors that determine how affect rate temperature affects the compare different ways of rate of reaction between measuring rate of reaction sodium thiosulfate and hydrochloric acid 6 Concentration, 8.6 pressure and reaction rate
Introduces the idea of one and two-step reactions 3 Distribution of stored energy Introduces the idea that frequency of collision is proportional to square root of the temperature. Introduces the distribution of energy. Explain the shape of different energy –level diagrams, including two-step reactions. Draw the Maxwell-Boltzmann distribution of stored energy in gas molecules Explain the shape of the curve 3.1.5.2 Maxwell–Boltzmann distribution Maxwell–Boltzmann distribution of molecular energies in gases. Students should be able to draw and interpret distribution curves for different temperatures. 8.3 8.4 8.5 4 Determining rates of reaction Introduces the idea of zero, and second order with respect to different reactants. Investigation to calculate the order of a reaction from concentration-time graphs Recognise zero, first and second order reactions from concentration-time graphs interpret graphs of reactant concentration or product concentration against time calculate the rate of reaction by drawing tangents to the curve 3.1.5.3 Effect of temperature on reaction rate Meaning of the term rate of reaction. The qualitative effect of temperature changes on the rate of reaction. Students should be able to use the Maxwell–Boltzmann distribution to explain why a small temperature increase can lead to a large increase in rate. AT a, b, k and l PS 2.4 and 3.1: Students could investigate the effect of temperature on the rate of reaction of sodium thiosulfate and hydrochloric acid by an initial rate method. 8.6 5 Initial rate method Introduces the initial rate method and how it can be used to determine how temperature affects the rate of reaction between sodium thiosulfate and hydrochloric acid describe how to find the initial rate of reaction explain how to use the initial rate method to compare factors that affect rate compare different ways of measuring rate of reaction 8.6 6 Concentration, pressure and reaction rate 8.6 Boltzmann