Ammonia (NH3) clouds are present around some planets. Calculate the number of grams of ammonia produced by the reaction of 5.4 g of hydrogen with an excess of nitrogen. N2 + 3 H2 ->2 NH3

Answer 1

Use stoichiometry to convert g of H₂ to g of NH₃

g H₂ → mol H₂ → mol NH₃ → g NH₃

5.4 g H₂ x (1 mol H₂ / 2.02 g H₂) x (2 mol NH₃ / 3 mol H₂) x (17.03 g NH₃ / 1 mol NH₃) = 30.35 g NH₃ ~ 30. g NH₃ (rounded to 2 sig figs; NOTE! There is a decimal after the zero to indicate 2 sig figs.)