Question

At 2000 ∘c the equilibrium constant for the reaction 2no(g)⇌n2(g)+o2(g) is kc=2.4×103. part a if the initial concentration of no is 0.171 m , what is the equilibrium concentration of no?

Answer 1

Answer:

[NO] = 1.72 x 10⁻³ M.  

Explanation:

• For the reaction:

2NO(g) ⇌ N₂(g)+O₂(g),

Kc =  [N₂][O₂] / [NO]².

• At initial time: [NO] = 0.171 M,  [N₂] = [O₂] = 0.0 M.

• At equilibrium: [NO] = 0.171 M - 2x ,  [N₂] = [O₂] = x M.

∵ Kc =  [N₂][O₂] / [NO]².

∴ 2400 = x² / (0.171 - 2x)² .

Taking the aquare root for both sides:

√(2400) = x / (0.171 - 2x)  

48.99 = x / (0.171 - 2x)  

48.99 (0.171 - 2x) = x  

8.377 - 97.98 x = x

8.377 = 98.98 x.

∴ x = 8.464 x 10⁻².

∴ [NO] = 0.171 - 2(8.464 x 10⁻²) = 1.72 x 10⁻³ M.  

∴ [N₂] = [O₂] = x = 8.464 x 10⁻² M.