Some basic household chemistry

Friday 22 February 2019

Health and Safety requirements in all schools are important and teachers and students should always consider the short-term and long-term hazards associated with chemicals in the laboratory but what about the chemicals that are routinely present in their own homes? The American Chemical Society has released a video entitled “Can mixing household cleaners kill you? (or, as it says more prosaically in the video, “Is death by toilet bowl cleaning a real thing?”)

"Can mixing household cleaners kill you?" by the American Chemical Society

The video takes you through some of the different types of cleaning agents found in a typical household and considers what products can be formed if they are either inadvertently or deliberately mixed. The household cleaners include bleach (sodium hypochlorite), ammonia solution, propan-2-ol and ethanol as well as different types of drain cleaner (e.g. sodium hydroxide, hydrochloric acid, sulfuric acid and hydrogen peroxide). Since your students are likely to have many of these products in their own home it could prove a useful exercise to get them to predict what products could actually be produced when two or more of them are mixed and write the relevant equations.  Much of it is acid-base or redox chemistry but thermochemistry can be invoked when acids and alkalis are added together and the shapes and polarity of molecules can be brought in with chloroamine and the di- and tri-chloroamines etc. You could also ask your students to provide the IUPAC names for many of the common names used such as isopropyl alcohol, chloroform and chloroacetone

For a Nature of Science exercise ask your students to critically appraise how accurate the chemistry in the the voiceover is. Do they agree with statements such as “sodium hypochlorite is a reactive molecule”, and “ammonia is a 5-10% solution of ammonium hydroxide, NH4+Cl”?



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