You Have Safety Questions? We Have Safety Answers!

By the STAO Safety Committee
The STAO Safety Committee welcomes enquiries, with respect to safety issues, from STAO members. Please send your questions to the Safety Committee Chair (refer to page 4 ‘Committee Chairs’). Your questions and the STAO Safety Committee responses may be published in Crucible, particularly if the information is deemed of general interest to other STAO members. Anonymity, however, will be guaranteed.

QUESTION #24:
I currently teach senior and International Baccalaureate chemistry at a school located in Ottawa. Recently I made a manometer (using just water) for measuring quantitatively the volume of evolved gas in some conventional chemistry activities. I wonder if I can replace the water with around 200 g of mercury (by considering all possible safety measurements) to enhance my capability to measure larger volume of evolved gas in my IB chemistry experiments. Your advice is highly appreciated.

RESPONSE: As you are likely aware, exposure to mercury vapour is extremely hazardous. Some Boards of Education have banned the use of mercury in schools so you need to check with the Board safety officer on whether its use is permitted in the school. If the Board has a ban on its use, this essentially prevents you from setting up the mercury manometer.

It is not recommended to proceed with using mercury in your manometer setup unless you ensure that the mercury is enclosed to prevent evaporative losses and precautions are taken to prevent spillage and breakage of the vessels. In addition, you should ensure that a plan is in place to decontaminate the room in case of spillage by using a mercury suction pump connected to a glass container, or a mercury collector foam pad. If keeping the mercury in the storage room, ensure that it is in a sealed container – a double or triple container system is highly recommended to contain spillage if the container leaks or breaks, otherwise arrange for safe disposal via a licensed contractor.