Australia's Science Forum

Our group just completed this prac last period. No mess, no fuss, no smell.
And all over for another year!!
Julie

Narelle, having expressed your concern to the teacher with an unsatisfactory result, can you then take it to the head of the OH&S committee? Take the relevant paper work with you. It isn't fair to put the kids through it when they are just doing what they are told!

I wouldn't even know who the OH&S people are in this school.

maybe its 1 committee i need to be on.

Ask someone in the office. Yes, you should get on it!! It is standard practice at our school I didn't even get a choice!

Some hints for bromine:
When using an ampoule have the water COLD and in an ice bath...bromine dissolves more easily in cold water.
Place the ampoule in the water and break top off under water...then as bromine comes out stir and keep stirring!All done in a fumehood of course.Store in a brown bottle .Dropper bottles are OK however must be used in the fumehood and the droppers of course will corrode.

That website is good, lots of tips.

Thanks
Rita

Wow, I didn't realize how seasonal this job could be. I see that there have been a few posts this week already about Bromine water. A teacher here has also asked for 10 dropper bottles of bromine water. Having caught a whiff of this stuff once, I don't think I'd want to use it outside of a fume cupboard, but if you read CSIS is says to use it in "a fume cupboard if practicable, otherwise use small quantities in a well-ventilated area".
Some questions: I have a bottle in the fridge labelled "bromine water", not sure of the age, but there is certainly not enough to even half fill 10 dropper bottles. In the chemical store there is a bottle with "Bromine Liquid, 1mL" from Chem-Supply. I haven't opened it but can I assume that this is the ampoule others have talked about? Someone mentioned in a post that they buy Bromine Water, is this all ready to go, which involves no mixing on my part?
I like the idea of handing the ampoule to the teacher and let him deal with it! I'm not comfortable with handling something like this just yet. I'm hoping that what is in the fridge will be enough to get them through the prac. (I'm thinking it might be a good idea to go and clean up the old prep room in another building during this prac!)

Yes Merilyn, the bromine water I buy is in a 500ml bottle ready to use. No mixing.
The ampoule is a small sealed glass container that you break in half, containing the concentrated toxic stuff.
Not for me, I won't even touch one.
I know you only use a small amount, and it has a short shelf life, but I don't care. Life is too short already without making it shorter or more difficult.
J

Thanks, J, I'll put the ready made on my shopping list for next time. I managed to half fill 8 dropper bottles from what was already there, don't know how old it is or how effective, but that's all they're getting!
It makes you wonder what all the contact with these chemicals must have on us. I often wonder what stories we'll be telling everyone in 20 years. It wasn't all that long a go that everyone thought DDT was a wonder pesticide!
Have a great Friday and a better weekend!

When I did this prac recently, I made the Bromine water using this recipe:

In order to make 50mL Bromine water, you will need:

• Glass bottle with screw cap, label the bottle Br2(aq)
• 1.1 g sodium bromide, NaBr
• 10.7 mL 1 M HCl
• 7.6 mL sodium hypochlorite (household laundry bleach)
• 32 mL water (preferably distilled water)

Dissolve the NaBr in the HCl and transfer to the labelled bottle. Add the sodium hypochlorite to the bottle and swirl to mix the reagents. Keep the bottle capped when not in use.

I leave a bottle of Sodium Thiosulfate solution with the prac so that in the event of a spill, it can be poured over the Bromine water to neutralise it and then I use it to neutralise any excess Bromine water. I also rinse out all the used glassware with sodium thiosulfate solution as well.

Just to throw the cat among pigeons, when I first started here (12 years ago), they used ampoules of Br to make Br water. I had a terrible accident when the ampoule broke in my hand and the liquid spilled onto my hand. It is very corrosive, I sustained 3rd degree burns and NEVER used liguid Br again. I buy Br water from Serrata. Very easy, no mess no worries.

Lada

Thanks whspa
Just got back on deck after 3 weeks long service leave, to be asked for bromine water for Period 5 today. Have just finished making up your recipe, as I couldn't find our bottle of Br water, and it was easy. Thanks very much. Just have to label it now, and get out the other chemicals. Don't you love lots of notice!! Over half our science staff are casuals or temps and pretend they don't know the rules; I'm tired of telling them. So if it can be done and they are nice about it, I do it.
Thanks again whspa

In relation to the "ready to use" bromine water, does anyone know how long it lasts for, both unopened and opened?
Thanks
M.

I checked my opened bottle of Bromine water the date received on the
bottle is 2002, this was used last week and gave good results.

Wow, that's encouraging! I was expecting it to be only good for a short period. Thanks for the info.
M.