I had to calculate the Fe2+ content of iron tablets and capsules. I've done the analysis for the capsules so this is just for the tablets.
SO I used 2 tablets. Total mass of these two is 0.54g.
I used 0.005 M potassium permanganate (this is the burette content). Prior to titration, I had to crush the tablets and add 100cm3 of 1 M sulfuric acid. Transfer to a 250cm3 volumetric flask. Use deionised water to fill up to the graduation line. Transfer this to a conical flask using a 25cm3 pipette, then add excess 10cm3 sulphuric acid (the same one used a while ago). Got an average titre of 14.9cm3. Did the calculations..
5Fe2+ + MnO4- + 8H+ ---> Mn2+ + 5Fe3+ + 4H2O
I found the moles of the potassium permanagante, used the above equation to use the ratio, multiplied the moles of potassium permanganate by 5 to get the moles of Fe2+. Then divided it by 10 to get the moles of Fe2+ in the 250 volumetric flask (as I used 25cm3 glass pipette to transfer the solution to the conical flask).
I then calculated for the mass using the rfm of iron by multiplying the calculated moles by 56. The mass is divided by two (as I used two tablets). then I converted it to mg by multiplying by 1000.
Why is the value so big.