Robert S. answered • 03/20/21

Patient PhD Chemist with 40 Years of R&D And Teaching

Hello, Juan,

The equation says we need 3 moles of H_{2} for every 2 moles of NH_{3} produced.

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

(3 moles H_{2})/(2 moles NH_{3}) * (1.84 moles NH_{3}) = 2.91 moles H_{2}. Multiply by the molar mass of H_{2} to find grams. I get 5.82 grams.

Bob