chemistry question

Question

Ammonia (the stuff used in floor cleaners) is manufactured using the Haber process, a high temperature process where gaseous hydrogen and nitrogen react according to the equation below.

N2 (g) + 3 H2 (g) \longrightarrow ⟶ 2 NH3 (g)

If 26.7 g of nitrogen gas are reacted, how many grams of hydrogen gas are required to use up all of the nitrogen?

Answer 1

N₂(g) + 3H₂₍g) ==> 2NH₃(g)  Balanced equation

From the balanced equation, note the mole ratio is 1 moles N₂ reacts with 3 moles H₂.  So, if you know how many moles of N2 are used, you can find the moles of H₂ required.  It will simply be 3x as much.  Once you know how many moles of H₂ are needed, you can easily convert that to grams of H₂ needed.

moles N₂ present = 26.7 g N₂ x 1 moles N₂/28 g N₂ = 0.954 moles N₂

moles H₂ needed = 0.954 moles N₂ x 3 moles H₂/mole N₂ = 2.86 moles H₂ needed

grams H₂ needed = 2.86 moles H₂ x 2 grams/mole = 5.72 g H₂ needed