In the reaction of Nitrogen gas with hydrogen gas to form ammonia gas, how many grams of hydrogen are needed to produce 1.80 grams of ammonia

Question

N2+3H2 -> 2NH3

Answer 1

Write a balanced chemical reaction:

N₂ + 3H₂ ==> 2NH₃

Looking at the mole ratios in this balanced equation you can see it takes 3 moles H₂ to make 2 moles NH₃.  So, next calculate the moles of NH₃ represented by 1.80 g and then convert to moles of H₂ needed:

moles of NH3 = 1.80 g x 1 mole/17 g = 0.106 moles NH3

Moles H₂ needed = 0.106 moles NH₃ x 3 moles H₂/2 moles NH₃ = 0.159 moles H₂ needed

Grams H₂ needed = 0.159 moles x 2 g/mole = 0.318 grams H₂ needed