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What chemical compounds might be present in drinking water?
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.
First Published: 23/03/2015
Updated: 04/10/2019
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2) That said, I had expected greater coverage on the typical water treatment process, which was finally introduced in "4.1.1".
3) The reader may well benefit from taking an introductory/refresher chemistry course before commencement.
4) The activities and videos assist the readers greatly in ensuring that the content has been fully understood.
5) After taking this course I decided to investigate why thallium receives no attention within the WHO, EU and UK regulations, but does within the US.
6) Some minor errata:
1 phosphororus -> phosphorous
1.1 “What will the [H+(aq)] be in the water in Figure 1?“
‘Figure 1’ -> ‘Figure 2’
Activity 1 the following URL yields serious security alerts:
Drinking Water Inspectorate, DWI (2015) of England and Wales ->
http://www.open.ac.uk/libraryservices/resource/website:40702
I ended up using:
https://dwi.gov.uk/consumers/learn-more-about-your-water/water-hardness-hard-water/
https://dwi.gov.uk/drinking-water-standards-and-regulations/
Question 4: “Note this is often artificially added to water supplies” …”often” is perhaps an overstatement, given the small number of water suppliers that have a statutory obligation, given the presence of fluoride within the source supply. For example: “6 million people in England live in areas with water fluoridation schemes, mainly in the West Midlands and the North East” https://www.gov.uk/government/publications/health-and-care-bill-factsheets/health-and-care-bill-water-fluoridation [recommended 0.7mg/l]
2.1.3 “t the shape of nitrate“
4.1.2 Reveal answer: Aluminum -> Aluminium (in the UK at least!)
Glossary: Oxidisation number “has has”