First, let's find the moles of hydrogen used to produce the ammonia mol = mass ÷ molar mass if the mass of hydrogen = 6.89 × 10⁻⁴ g & the molar mass of hydrogen = 2 g/mol then moles of hydrogen = (6.89 × 10⁻⁴ g) ÷ 2 g/mol moles of H₂ = 3.445 × 10⁻⁴ mol
Next, balanced eq'n for the production of ammonia from hydrogen gas and nitrogen gas: N₂ + 3H₂ → 2NH₃
Now, the mole ratio (ratio of the coefficients used to balance the equation) of H₂ : NH₃ is 3 : 2
∴ if the moles of H₂ = 3.445 × 10⁻⁴ then based on the mole ratio, the moles of NH₃ = [(3.445 × 10⁻⁴) ÷ 3] × 2 = (1.14833 × 10⁻⁴) × 2 ∴ mole of NH₃ = 2.2967 × 10⁻⁴ Now, # of molecules = moles × Avogadro's Constant ∴ # of molecules of NH₃ = (2.2967 × 10⁻⁴) × (6.02 × 10²³) = 1.383 × 10²⁰ molecules Thus, the molecules of NH₃ produced is ≈ 1.38 × 10²⁰ molecules.
