Question

A chemist wants to produce 5 grams of ammonia (NH3) gas through the reaction of nitrogen gas (N2) and hydrogen gas (H2). What mass of hydrogen gas is needed, assuming excess nitrogen gas is provided? (Hint: balance the chemical equation and use stoichiometry to calculate the required mass)

Answer 1

First, we need to balance the chemical equation for the formation of ammonia:N2 + 3H2  2NH3Now that we have a balanced equation, we can use stoichiometry to determine the mass of hydrogen gas needed to produce 5 grams of ammonia.1. Calculate the molar mass of ammonia  NH3 :N: 14.01 g/molH: 1.01 g/molMolar mass of NH3 = 14.01 +  3  1.01  = 17.03 g/mol2. Convert the mass of ammonia to moles:5 g NH3   1 mol NH3 / 17.03 g NH3  = 0.293 mol NH33. Use the stoichiometry of the balanced equation to find the moles of hydrogen gas needed:0.293 mol NH3   3 mol H2 / 2 mol NH3  = 0.4395 mol H24. Convert the moles of hydrogen gas to mass:0.4395 mol H2   2.02 g H2 / 1 mol H2  = 0.888 g H2Therefore, 0.888 grams of hydrogen gas is needed to produce 5 grams of ammonia, assuming excess nitrogen gas is provided.