Question

Calculate the number of grams of H2O that will form on decomposition of 0.10 mole of ammonium nitrate.

Answer 1

Here's the reaction: NH4NO3 Δ→ N2O + 2H2O.
From it, we see that for every mole decomposed, two moles of water are formed. Therefore if 0.10 moles decomposes, 0.20 moles of water will form.
mass H2O = (18.00 g/mol) (0.20 mol) = 3.6 grams.