chemistry

A general discussion and Q & A forum.
Post Reply
glenpaul
Posts: 25
Joined: 23 Aug 2011, 11:46
State/Location: NSW

chemistry

Post by glenpaul »

Hi
Does anyone have success when filtering Barium Sulfate? We use Buchner Funnels with the filter paper for barium sulfate from Sc Supply and vacuum pumps on taps but we still don't seem to have success as the sulfate goes through the paper and the solution in the side arm flask is always milky.
User avatar
rae
Posts: 1045
Joined: 31 May 2006, 10:00
School: Oxley College
Suburb: Burradoo
State/Location: NSW

Re: chemistry

Post by rae »

We use Gooch crucibles with the side arm flasks and vacuum pumps and have had great success. The gooch crucible is a sintered glass crucible with a porcelain filter in the bottom. I think the No.4 is what you need. They are expensive but have always worked for us.
User avatar
sunray18
Posts: 1488
Joined: 14 Feb 2008, 12:30
State/Location: NSW

Re: chemistry

Post by sunray18 »

Buy Whatman filter papers - No 40 could be the one you need but ask the supplier. They are expensive.
User avatar
Mother
Posts: 275
Joined: 17 May 2006, 10:00
Job Title: Science lab. technician
School: Dubbo College/Senior Campus
Suburb: Dubbo
State/Location: NSW

Re: chemistry

Post by Mother »

I was going to suggest Whatman Grade 42 filters.
Mother
User avatar
Loopy
Posts: 591
Joined: 08 Jun 2006, 10:00
School: Mater Dei Catholic College
Suburb: Wagga Wagga
State/Location: NSW

Re: chemistry

Post by Loopy »

We have good results using Chemistry Contexts 2nd edition prac 3.2 which uses a 0.1% agar solution as a coagulant.

It says " The BaSO4 precipitate is exceedingly fine and is extremely difficult to filter without the uses of agar solution as a coagulating agent. The procedure is valid because the filtrate is clear of any BaSO4 and any agar retained with the BaSO4 residue is of immeasurable mass. If all of the agar was retained, it would add 0.01g to the BaSO4 residue. The sensitivity of the standard laboratory electronic balance is 0.01g"

Hope this helps....
Lou P.
Learner Lab Technician
Wagga Wagga
NSW
User avatar
rae
Posts: 1045
Joined: 31 May 2006, 10:00
School: Oxley College
Suburb: Burradoo
State/Location: NSW

Re: chemistry

Post by rae »

Loopy is it possible to get a copy of that prac?
User avatar
Loopy
Posts: 591
Joined: 08 Jun 2006, 10:00
School: Mater Dei Catholic College
Suburb: Wagga Wagga
State/Location: NSW

Re: chemistry

Post by Loopy »

I will try. My IT capabilities rate very low!....
Lou P.
Learner Lab Technician
Wagga Wagga
NSW
User avatar
Loopy
Posts: 591
Joined: 08 Jun 2006, 10:00
School: Mater Dei Catholic College
Suburb: Wagga Wagga
State/Location: NSW

Re: chemistry

Post by Loopy »

Here goes, sorry about the writing on the pages....
You do not have the required permissions to view the files attached to this post.
Lou P.
Learner Lab Technician
Wagga Wagga
NSW
User avatar
rae
Posts: 1045
Joined: 31 May 2006, 10:00
School: Oxley College
Suburb: Burradoo
State/Location: NSW

Re: chemistry

Post by rae »

Thanks Loopy it worked a treat!!
User avatar
ELIZABETH
Posts: 233
Joined: 02 Jun 2006, 10:00
School: O'Connor Catholic College
Suburb: Armidale
State/Location: NSW

Re: chemistry

Post by ELIZABETH »

Thanks indeed!
glenpaul
Posts: 25
Joined: 23 Aug 2011, 11:46
State/Location: NSW

Re: chemistry

Post by glenpaul »

Hi Loopy
Is it possible to have a copy of the "Barium Sulfate /Agar" prac too.
Thanks
Glenpaul
User avatar
Loopy
Posts: 591
Joined: 08 Jun 2006, 10:00
School: Mater Dei Catholic College
Suburb: Wagga Wagga
State/Location: NSW

Re: chemistry

Post by Loopy »

Hi all,
I hope the prac works well for those who try it. Glenpaul, I think the pdf is till available on this page for you to download. Let me know if there are any problems.
Lou P.
Learner Lab Technician
Wagga Wagga
NSW
Post Reply