Australia's Science Forum

We have finally done this prac and got good results finally for the first time. They used agar as a coagulating agent, and it worked a treat. Everyone else may already have this info, but just in case you are still scratching your head, there is a way to make it work. Cheers

But how did they do it?

I spent last thursday afternoon trying out different methods and achieved a good deal of success with a buchner funnel and several layers of our special filter paper, a water powered venturi pump and most of all patience as I only put about a ml at a time through the filter paper.

Also the recipe that used HCl and Baruim Chloride and booiling the mixture worked a lot better then just adding Barium Nitrate to the disolved fertiliser.

I would love instruction on how you used agar as a coagulating agent.

Thanks
Wendy

The trick to filtering barium sulphate is to use a glass filter crucibe (sinter) No.4, this is specially designed to filter the ultra fine BaSO4. Any vacuum will do, but it is a much quicker job if you have access to an electric pump.
Regards
Jenny Walter

Hi Wendy
The procedure they used came directly from Chemistry Contexts 2 Second edition Lab Manual Chapter 3. It is about 5 pages in all, but the main stuff is on one page which I can fax if you'd like. If I can find out how to scan stuff I could put it on here as an attachment. I tried to send you a PM this morning on this, but it went off into the ether somewhere! So I put it on as a topic instead, in case others wanted it as well. It doesn't need sintered glass crucibles (which I couldn't buy in the past) either.

Just saw the scanning gurus so will attach the instructions. Ooops I think it will go through as 4 files. Page 2 is the main one.

These attachments look weird on my computer and don't download. It is the same for everyonelse? If so I will try and fix it.

Yes I can not open them at all. On another computer, they are so strange.

same for me, I cant open them either .

Me either
the last time I opened something strange I caused all sorts of problems to the emails of 5000 people

Sorry guys, been flatstrap for a few days. Will go now and try to find someone to help me fix this. Don't hold your breath, but I will be working on it.

Here goes for another try.

Thank you that is great now. Well done.