Question

An important industrial process for synthesizing the ammonia used in agricultural fertilizers involves the combination of N2 and H2 

N2(g) +3H2(g) ⇌ 2NH3(g)  Kc= 3.654 x 10⁸ at 69.25 °C 

What is the value of Kp of this reaction at 69.25 °C? 

Answer 1

Consider a given reaction N ₂ (g) + 3 H ₂ (g) 2 NH ₃ (g)  

For this reaction, n = number of moles of gaseous products - number of moles of gaseous reactants

n = number of moles of gaseous NH ₃ - [ No. of moles of gaseous N ₂ + number of moles of gaseous H ₂ ]

n = 2 - ( 1+3) = 2 - 4 = - 2

We have relation, K _p = K _c ( RT) ⁿ

Given : K _c = 3.654 10 ⁸ , R = 0.082057 L atm mol ^-1 K ^-1 , T = 69.25 + 273 = 342.25 K

K _p = 3.654 10 ⁸ ( 0.082057 342.25 ) ^{- 2}

K _p = 4.633 10⁵