Question

Ammonia is produced from its elements in a formation reaction. If 7.68 x 1024 molecules of ammonia are produced, how many moles of hydrogen were used?

Answer 1

Solution:

A chemical equation must be balanced:

N₂ + 3H₂ = 2NH₃

amount n = Number of particles N / Avogadro constant N_A

According to the reaction equation for 2 mol of NH₃ are needs 3 mol of H₂

And then, calculate moles of H₂

n of H₂ $= (3× 7.68×10^24)/(2× 6.02×10^24 )$ = 1.91 mol

Answer: were used 1.91 moles of H₂