Mg3N2(s) + H2O ----> Mg(OH)2 + NH3?

Question

What is the maximum mass of NH3 that can be produced when 49.0g of Mg3N2 and 25.0g H2O react. I just dont know how to set it up. What I did was 49.0g Mg3N2/1 * 1mol Mg3N2/100.9284g Mg3N2 * 2mol NH3/1mol Mg3N2= 0.97 mols which should be about 16.52 g. However when I put this it it came up wrong.

Thanks
Bibbity

Answer 1

You've got to work out whether there's enough water for all the magnesium nitride to react.
You must also balance the equation!
Work out the moles of Mg3N2. Work out the moles of H2O. If the moles of H2O is less than 3 x the moles of Mg3N2, then it is the limiting reagent.
Your problem then will work out something like
25/18 x 2/3 x 17.