# Problem: Given the reaction2NH3(g) ⇌ N2(g) + 3H2(g)At equilibrium, it was found that the concentration of H2 was 0.0591 M, the concentration of N2 was 0.0197 M, and the concentration of NH3 was 0.441 M. What is Kc for this equilibrium?A) 3.97 × 10–3B) 1.58 × 10–5C) 2.10 × 10–5D) 2.24 × 10–1E) 2.65 × 10–3

###### FREE Expert Solution

We’re being asked to determine the equilibrium constant this reaction:

2 NH3(g)  N2(g) + 3 H2(g)

Recall that the equilibrium constant is the ratio of the products and reactants

We use Kp when dealing with pressure and Kc when dealing with concentration:

$\overline{){{\mathbf{K}}}_{{\mathbf{p}}}{\mathbf{=}}\frac{{\mathbf{P}}_{\mathbf{products}}}{{\mathbf{P}}_{\mathbf{reactants}}}}$     $\overline{){{\mathbf{K}}}_{{\mathbf{c}}}{\mathbf{=}}\frac{\mathbf{\left[}\mathbf{products}\mathbf{\right]}}{\mathbf{\left[}\mathbf{reactants}\mathbf{\right]}}}$

Note that solid and liquid compounds are ignored in the equilibrium expression.

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###### Problem Details

Given the reaction

2NH3(g) ⇌ N2(g) + 3H2(g)

At equilibrium, it was found that the concentration of H2 was 0.0591 M, the concentration of N2 was 0.0197 M, and the concentration of NH3 was 0.441 M. What is Kc for this equilibrium?

A) 3.97 × 10–3

B) 1.58 × 10–5

C) 2.10 × 10–5

D) 2.24 × 10–1

E) 2.65 × 10–3