ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: lacoste on March 15, 2009, 10:41:58 pm

Title: gravimetric analysis of sulfate in fertiliser
Post by: lacoste on March 15, 2009, 10:41:58 pm: The barium sulfate precipitate was higher than the actual mass of the fertiliser, is this correct or errors in prac?
Title: Re: gravimetric analysis of sulfate in fertiliser
Post by: TrueTears on March 15, 2009, 11:03:56 pm: wow we did this prac last week,

it is not an error, the $BaSO_4$ is the precipitate, the $Ba^{2+}$ ions have nothing to do with the fertiliser so that might make the precipitate heavy, all we need to care about is the $SO_4$ which is the actual ingredient of the fertiliser ( i assume the active ingredient of the fertiliser is $(NH_4)_2SO_4$ . coz it was in our prac)

I got a value of $BaSO_4$ larger than the mass of my fertiliser (in the prac i did at school) but when i worked out the % by mass of $(NH_4)_2SO_4$ it matched the label.
Title: Re: gravimetric analysis of sulfate in fertiliser
Post by: lacoste on March 16, 2009, 08:30:32 am: yeh same prac as you!!!

i didnt get the percentage on the fertiliser.

what brand fertiliser did u use and what percentage true tears?

many thanks!!
Title: Re: gravimetric analysis of sulfate in fertiliser
Post by: TrueTears on March 16, 2009, 05:57:08 pm: I think we used "Brunnings up lawn food" or something like that as the fertiliser

and % of Nitrogen i got was around 11%

and % of $(NH_4)_2SO_4$ was around 50-60 % (can't remember the exact value)