chmical equilibrium

2008-02-11 8:17 pm

1.25 mol NOCl was placed in a 2.5L reaction chamber at 427度. after equilibrium was reach, 1.1 mol NOCl remained. calculate the equilibrium constant K for the reaction
2NOCl(g)=2NO(g)+Cl2(g)
ans:k=5.6*10^-4

回答 (1)

Uncle Michael

2008-02-11 8:50 pm

✔ 最佳答案

2NOCl(g) = 2NO(g) + Cl2(g)
Initial concentrations :
[NOCl]o = 1.25/2.5 = 0.5 mol dm-3
[NO]o = [Cl2]o = 0 mol dm-3

Changes in concentration from the initial stage to the equilibrium :
Δ[NOCl] = (1.1/2.5) - 0.5 = -0.06 mol dm-3
Δ[NO] = +0.06 mol dm-3
Δ[Cl2] = +0.06/2 = +0.03 mol dm-3

Equilibrium concentrations :
[NOCl]eq = 1.1/2.5 = 0.44 mol dm-3
[NO]eq = 0 + 0.06 = 0.06 mol dm-3
[Cl2]eq = 0 + 0.03 = 0.03 mol dm-3

Equilibrium constant K
= [NO]eq2 [Cl2]eq / [NOCl]eq2
= (0.06)2 x (0.03) / (0.44)2
= 5.6 x 10-4 mol dm-3

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