Precipitation reactions: I am looking for precipitate reactions that have the least impact on the environment but are also dramatic. Do you have any suggestions?

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Precipitation reactions: I am looking for precipitate reactions that have the least impact on the environment but are also dramatic. Do you have any suggestions?
Microscale Chemistry: Can you provide some information on microscale chemistry please?
Biodiesel: Do you have a method or advice that you can recommend for making biodiesel? I am concerned about the safety and waste disposal aspects.
Hydrogen peroxide storage: I have stored H2O2 in the fridge in the Chem Prep room for years but recently I have been part of discussions that say this should never be the case
Storage of sodium metal:
Cleaning and reuse of a plastic container that previously held 10M HCl: I have a large (2.5L) commercial stock plastic container that is empty.
Laboratory coats and aprons: What types of lab coats or aprons should be used in a school laboratory? What should they be made of?
Barium nitrate solutions: Is a 0.1M solution of barium nitrate permissible for years 7-10 in NSW Department of Education Schools? It is not clear in the CSIS chemical search.
Decommissioning a science area: Our school is building a new science area and will be decommissioning the existing science rooms. What advice can you provide on this process please?
Potassium iodide status and EUDs: Can you confirm whether potassium iodide is allowed in WA schools and can you explain what an EUD is?