Question

2. The pressure dependence of the following system at equilibrium was studied at 500°C by measuring the mole fractions of ammonia that were produced at various pressures from 1:3 mixtures of N2 and H2 gases. Assume ideal gas behavior. (Hint: You may assume that the mixtures were prepared from 1 mole of N2 mixed with 3 moles of H2). (10 pts) Ng(g)+H,(g)P NH,(g) P/(bar) 100 XNH3 0.10 200 0.18 300 0.25 400 0.32 500 0.37 600 0.42 700 0.46 800 0.50 900 0.53 1000 0.56 (a) Write the expression of Kp. (b) Using data include in the table above, calculate Kp and the partial pressures of the three gases at equilibrium when the pressure is 100 bar.

Answer 1

Ź N2 + 2 H₂ Ž NH3 Intial mole Chang IK In UM o+M oth Equilibrium (1-21) (3-31) Total mole at Equilibrium - 1- th +3-} mole fraction XNH3 = &n =4-2 oth Giveing that @ loobar n or 0.10 = XNH2= o.lo than 0.40 - olon = x U-n 0.40 = lin or n = oil = 0.3636

mole fraction XN2 = IN 1- - 013636 - z -0.2182 un u-0.3636 3.6364 (Xm2 = 012250 mole fraction of H₂ XH₂ = 3-1 3-340.3636 4-n 2.4546 3.6364 4-0.3636 Jyn₂ = 0.675 kp = (Pong) (Pre) ² ( Pu2 / total Pressure - p= 100 ban than PN2 = XN2 P = 0.225 X 100 = 22.5 bar Pastial Pressuu -PH2 = XH2P = 01675*100= 67.5 bar "PNHS - Ynna Paolox10o = 10 bar Kp = lo but 10 (22.5 bax)(67,53312 - 4.7434x554.569 kp = 3.801 103, baril bout