Question

Bomai places 7mol of Ammonia (NH3) in 14L flask.At Eqiulibrium 0.2M Ammonium (NH4
+
) was found in the flask. What is the equilibrium constant Kc for this reaction?
I) Write a balanced chemical reaction for the above reaction.(1mark)
II) What is the equilibrium constant Kc for this reaction?

Answer 1

I) Balanced chemical reaction:
NH3 (g) ⇌ NH4+ (aq)

II) The equilibrium constant expression for this reaction is:

Kc = [NH4+] / [NH3]

Since the initial amount of NH4+ is 0 M and the equilibrium amount is 0.2 M, and the initial amount of NH3 is 7 mol and the volume is 14 L, the concentration of NH3 at equilibrium is:

[NH3] = 7 mol / 14 L = 0.5 M

Therefore, the equilibrium constant Kc for this reaction is:

Kc = [0.2] / [0.5] = 0.4