[livelovelaugh146]

Doing higher chemistry and i have a question that says

In one investigation it was found that an average of 29.5cm^3 of 0.02moll-1 iodine solution was required to react completely with 25cm^3 of vitamin C solution.
Use this result to calculate the mass in grams of vitamin C present in each tablet.

I've tried doing the gfms and no. of moles of iodine solution but i just dont understand.

Thanks for any help

[Grundalizer]

29.5 cm³ = 29.5 mL @ 0.02 M (I am assuming?...what is moll-1?) = 5.9 x 10 ^-4 mol of Iodine.  Iodine reacts with vitamin C to make some dehydro acid  thingy, I don't remember exactly, but I JUST did the lab and its a 1:1 molar ratio reaction.  So, if the above mentioned amount of iodine reacted with 25 mL of vitamin C, we find that there are 5.9 x 10 ^-4 Vitamin C IN 25 mL of solution, which means its a bit more than 0.02 M.  I think you've left something out though. 

Usually in a lab like this, you take a small portion of the tablet, certain mass, grind it up and dissolve it in 25 mL or so.  Then use the data to find how much is in that small sample, and multiply it by how many "little pieces" that size are in the larger tablet. 

I think you took the mass of the tablet somewhere, and the mass of the little bit of Vitamin C tablet you put in 25 mL.  Hook me up with that and I can try and help you a little more.