Question

7. The synthesis of ammonia from the elements is conducted at high pressures and temperatures: N2(g) +3 H2(g) 2 NH3(g) Suppose that at one stage in the reaction, 13 mol NH3, 31 mol N2, and 93 mol H2 are present in the reaction vessel at a total pressure of 210 atm. Calculate the mole fraction of NH3 and its partial pressure.

Answer 1

Ans 7:

Total pressure of the mixture = P_T = 210 atm

Let the number of moles of N₂ in the mixture be = n1 = 31 moles

Let the number of moles of H₂ in the mixture be = n2 = 93 moles

Let the number of moles of NH₃ in the mixture be = n3 = 13 moles

Let the total number of moles in the mixture be n = n1+ n2 + n3 = 31 + 93 + 13 = 137 moles

Mole fraction of NH₃= n3/n = 13/137 = 0.0949 = χ_NH3

Partial pressure of ammonia = χ_NH3 x P_T = 0.0949 x 210 = 19.929 atm.