If you needed to produce 33.0 g of NH3, how many grams of H2 would you need? (Stoichiometry)

Question

Consider the following balanced chemical reaction:

    N₂ + 3 H₂ → 2 NH₃

If you needed to produce 33.0 g of NH3, how many grams of H2 would you need?

Answer 1

Hello, Juan,

The equation says we need 3 moles of H₂ for every 2 moles of NH₃ produced.

Convert 33.9 g of NH₃ to moles by dividing by it's molar mass.The molar mass is 17 g/mole, so that means we have 33.9g/7g/mole or 1.94moles NH₃. To get this amount of NH₂, we need to adjust by the molar ratio of the H₂/NH₃, which is 3/2:

(3 moles H₂)/(2 moles NH₃) * (1.84 moles NH₃) = 2.91 moles H₂. Multiply by the molar mass of H₂ to find grams. I get 5.82 grams.

Bob