The theoretical yield of the reaction : 151.64 g
The limiting reactant : N₂
The excess reactant : H₂
Reaction
N₂+3H₂⇒2NH₃
A method that can be used to find limiting reactants is to divide the number of moles of known substances by their respective coefficients(mol ratio), and the smaller become a limiting reactant
mass of N₂=125 g
mol N₂(MW=28 g/mol) :
[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{125}{28}=4.46[/tex]
mass H₂ = 125 g
mol H₂(MW= 2 g/mol) :
[tex]\tt mol=\dfrac{125}{2}=62.5[/tex]
From the equation, mol ratio N₂ : H₂ = 1 : 3
Limiting reactant : N₂ : H₂ =
[tex]\tt \dfrac{4.46}{1}\div \dfrac{62.5}{3}=4.46\div 20.8[/tex]
N₂ : limiting reactant
H₂ : excess reactant
mol NH₃ based on limiting(N₂) (from equation N₂ : NH₃ = 1 : 2)
[tex]\tt mol~NH_3=\dfrac{2}{1}\times 4.46=8.92[/tex]
mass NH₃ (MW=17 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=8.92\times 17=151.64[/tex]
