ES Section 2 (f), (n), 7 hours Iodine–thiosulfate redox Main chemical ideas: equilibria. – – (o), (p), (q) titrations. Iodine–thiosulfate titrations are a new context. The use of chlorine in Using ideas of 'opposing Liberated iodine can be measured using bleach is used to introduce change' to predict the effect thiosulfate titrations, using starch as an iodine the concept of equilibrium of changing conditions on indicator, giving a clear endpoint. Titration and and calculations of the equilibrium position redox calculations can be taught here. equilibrium constant, as (HSW3). This is a key area of mathematical skills well as iodine–thiosulfate Techniques and development. Plenty of practice is titrations. This into a procedures in iodine and recommended. discussion of the risks and thiosulfate titrations benefits of using chlorine. (HSW4). Considering the risks associated with the transport and use of chlorine (HSW9). Considering the use of chlorine in sterilising water (HSW10). Le Chatelier's principle provides opportunities for modelling and developing problem solving skills.
ES – Section 2 – (f), (n), (o), (p), (q) The use of chlorine in bleach is used to introduce the concept of equilibrium and calculations of the equilibrium constant, as well as iodine–thiosulfate titrations. This into a discussion of the risks and benefits of using chlorine. 7 hours Iodine–thiosulfate redox titrations. Using ideas of 'opposing change' to predict the effect of changing conditions on equilibrium position (HSW3). Techniques and procedures in iodine and thiosulfate titrations (HSW4). Considering the risks associated with the transport and use of chlorine (HSW9). Considering the use of chlorine in sterilising water (HSW10). Le Chatelier's principle provides opportunities for modelling and developing problem solving skills. Main chemical ideas: equilibria. Iodine–thiosulfate titrations are a new context. Liberated iodine can be measured using thiosulfate titrations, using starch as an iodine indicator, giving a clear endpoint. Titration and redox calculations can be taught here. This is a key area of mathematical skills development. Plenty of practice is recommended.