[sinners]

I got a test tomorrow and am doing revision, i cam up to this question that i cant seem to get. Any help is greatly appreciated.

Phosphorus is an important plant nutrient and is therefore present in many fertilisers. It can be determined gravimetrically by carrying out a number of steps, eventually leading to it's precipitation as insuluble Mg2P2O7. In such an analysis, a 14.298g sample of fertiliser yielded 4.107g of Mg2P2O7 precipitate.

(a) Calculate the mass of phosphorus in the precipitate.

(b) Hence calculate the precentage of phosphorus in the fertiliser.

What i did was figure out the percentage composition of phorsphorus then apply that to the 4.107g however i didnt get the right answer

thanks

Josh

[Borek]

Sounds correct aproach, show what you did, could be some stupid mistake.