ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: bar0029 on March 14, 2011, 04:04:02 pm
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heya
in regards to the SAC-part 3: iron in fertilliser redox titration
theoretically to obtain 4.2% we are required to obtain a titre of 3.01L
however we obtained a titre of 7.65 mL and resulted in 0.016% w/w of Fe in the fertilliser
this is a major difference, obviously.
the only differences i can account for are:
- loss of fertilliser when changing glass ware (i.e. from one conical flask to the next when filtering) - my group did this three times
- loss of fertilliser when transferring it to the flask from the weighing balancer
- another substance was reducing the potassium permanganate, therefore underestimate of the titre of the KMNO4. however does this increase or decrease the amount of KMNO4?
- parallax error when reading the burette, conical flask etc.
- loss of sample in titration through splashing or neglecting to wash down the sides of the flask occasionally
- glass ware being 'dirty' i.e. contaminated with impurities.
is there any MAJOR ones i am missing?
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heya
in regards to the SAC-part 3: iron in fertilliser redox titration
theoretically to obtain 4.2% we are required to obtain a titre of 3.01L
however we obtained a titre of 7.65 mL and resulted in 0.016% w/w of Fe in the fertilliser
Umm just to ask, is that 3.01 LITRES? Because I've seen a lot of SACs and that titre looks a bit odd lol. Normal burretes can only contain approx 100mil of solutions. So you need to refill your burrete 30 times? I think there might be a calculation error somewhere lol. Your 7.65ml is probably more correct
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- another substance was reducing the potassium permanganate, therefore underestimate of the titre of the KMNO4. however does this increase or decrease the amount of KMNO4?
Since another substance is reducing the permanganate. MORE permanagate MUST be consumed to neutralise the Iron AS WELL as the random "other" substances. Therefore an overestimation of Iron mass or mol will result. This won't be the right reason for you since you are looking for a reason in which there's a UNDERestimation of Iron mols.
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okay okay fair enough
and yeah haha i know 3.01 litres i was like, WHAT THE :|
can you check over my solutions if i attach them ?
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okay okay fair enough
and yeah haha i know 3.01 litres i was like, WHAT THE :|
can you check over my solutions if i attach them ?
well I guess, I'm bored enough in uni, so go ahead