ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: zibb3r on March 01, 2012, 08:18:01 pm
-
For the prac where you determine the iron content in fertiliser (Heinemann workbook pg.53) I have written my method. Can you please check as we have to do the prac tomorrow and need verification that its ok because its a SAC and my teachere eisn't allowed to help.
So Please go ahead and pull it apart, and most of all tell me that it works!!! If not, know how to fix it?
1. collect previousy standardised KMnO4 in a 100ml beaeker.
2. Rinse all conical and volumetric flasks with deionised water
3. Accurately weigh X grams (How many grams?) of fertiliser and transfer to volumetric flask
4. Measure out 10 or 20 mls (I keep hearing different opinions, so is it 10 or 20mls? Or does it even matter?) of H2SO4 and add this to the flask
5. Add 20ml deionised water to solution, mix and then filter to remove insoluble compunds.
6. Return filtrate to volumetric flask and invert to mix
7. Rinse pipette with fertiliser soln and transfer 20ml aliquots to 3 conical flasks
'
8. Rinse and fill burette with the KMnO4 and record initial volume. (We have to have the burette filled with KMnO4, teacher said so.... So this isn't a changeable option)
9. Titratee until rxn is observed and record results
10. Repeat until concrodancy is achieved
THANKS SOOOOOO MUCH GUYS!!!!!!!!!!!!!!!!!!!!!!!
-
3. It doesn't really matter how many grams you measure out, because your calculations will be based on the figures that you use. You therefore should be told how many grams of fertiliser to use.
4. I'm not sure exactly, but the key thing here is to have an EXCESS of acid, and so I would stick with 20mL
Apart from that, the experimental design sounds fine to me, and I think there were a couple of other threads on this prac, so you might want to check out their experimental design as well.