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April 8, 2022


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Do you want to know what’s in the water that you drink?

This free course, What chemical compounds might be present in drinking water?, examines the chemical compounds that occur in drinking water. A high level of certain anions in water can cause environmental pollution and health problems. Cations are also important. For example, calcium salts contribute to the hardness of water and water treatment uses aluminium compounds. Additionally oxidising agents, such as ozone or chlorine, are vital in the disinfection of water. This OpenLearn course focuses on the chemistry of the p-block elements in Groups 13 to 18 of the Periodic Table.

Course learning outcomes

After studying this course, you should be able to:

  • Understand that in drinking water anions have a beneficial range of concentration above which they may have an adverse effect on either human health or the environment. Toxic elements and compounds often block essential biological processes
  • Explain how excess anions or cations in aqueous solution can be removed by ion-exchange chromatography or an ion-exchange membrane
  • Explain how cations such as aluminium can be amphoteric, that is they can neutralise both acidic and alkaline solutions. Also recognise how this enables aluminium(III) ions to be used in water treatment

Course Curriculum

  • Introduction 00:10:00
  • Learning outcomes 00:10:00
    • Water 00:15:00
    • The water cycle and drinking water 00:20:00
    • The toxicity of chemicals 00:20:00
    • Summary of Section 1 00:10:00
    • Anions in water 00:05:00
    • The nitrogen cycle 00:20:00
    • Natural nitrogen fixation 00:20:00
    • Arsenic pollution in the environment 00:15:00
    • Removal of arsenic oxoanions from drinking water 00:20:00
    • Summary of Section 2 00:15:00
    • Phosphorus compounds in water 00:10:00
    • Phosphoric acid and fertilisers 00:20:00
    • Polyacids 00:20:00
    • Nomenclature of oxoacids 00:25:00
    • Prediction of formulas 00:15:00
    • Condensation of oxoacids 00:20:00
    • Polyphosphates 00:30:00
    • Adenosine triphosphate 00:15:00
    • Summary of Section 3 00:15:00
    • Cations in water 00:15:00
    • Aqueous chemistry of aluminium 00:15:00
    • Aluminium sulfate in water treatment 00:20:00
    • Aluminium and biology 00:15:00
    • Aluminium toxicity 00:20:00
    • Toxicity of thallium(I) compounds 00:10:00
    • The inert pair effect 00:10:00
    • Home water filters 00:10:00
    • Summary of Section 4 00:10:00
    • Conclusion 00:10:00

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