2NH4NO3 --> 2N2 + O2 + 4H2O

What mass of H2O can be formed from the decomposition of 12.0 g of NH4NO3?

mols NH4NO3 = grams/molar mass

Use the coefficients in the baalanaced equation to convert mols NH4NO3 to mols H2O.
Now convert mols H2O to grams H2O. g = mols x molar mass

To determine the mass of H2O formed from the decomposition of 12.0 g of NH4NO3, we first need to calculate the molar mass of NH4NO3 and then use stoichiometry to find the ratio between NH4NO3 and H2O.

1. Calculate the molar mass of NH4NO3:
NH4NO3 = (1 × 14.01) + (4 × 1.01) + (1 × 14.01) + (3 × 16.00)
= 80.04 g/mol

2. Use stoichiometry to find the ratio between NH4NO3 and H2O:
From the balanced equation, we know that 2 moles of NH4NO3 decompose to form 4 moles of H2O.
Therefore, the ratio of NH4NO3 to H2O is 2:4, which can be simplified to 1:2.

3. Calculate the moles of NH4NO3:
Moles of NH4NO3 = mass / molar mass
= 12.0 g / 80.04 g/mol
≈ 0.1499 mol

4. Use the ratio to calculate the moles of H2O:
Moles of H2O = 0.1499 mol × (2 mol H2O / 1 mol NH4NO3)
= 0.2998 mol H2O

5. Calculate the mass of H2O:
Mass of H2O = moles of H2O × molar mass of H2O
= 0.2998 mol × 18.02 g/mol
≈ 5.40 g

Therefore, approximately 5.40 grams of H2O can be formed from the decomposition of 12.0 g of NH4NO3.