Posted by **Mary** on Friday, March 26, 2010 at 3:05am.

Hi

Can sombody please help me with this problem

If a soil sample contains 0.5g of iron (Fe3+) per 100g. The iron is precipitated when soil becomes alkaline as shown by equation Fe3+ + 3OH + (x-1)H2O ? FeOOH.xH2O(s)

The soil is sprayed with 50 wt% urea solution with density of 1.21g/ml

equation follows (H2N)2CO + H2O ? CO2+ 2NH4+ + 20H-

1) How do you express the concentration of Fe3+ in the soil sample in mmol/g?

2) How do you calculate the mass and the volume of urea solution needed to precipitate all Fe3+ in the soil sample?

Thanks