Answer to Question #118035 in Chemistry for Crizzia Paula Lobrido

Question

2. The reaction of bromine gas with chlorine gas, shown here, has a Kc value 0f 7.20 at 200°C. If a close vessel was charged with the two reactants, each at initial concentration of 0.200 M, but with no initial concentration of BrCl, what would be the equilibrium concentration of BrCl?

Br2(g) + Cl2(g) ⇄ 2BrCl(g) Kc=7.20
Initial Concentration 0.200 0.200 0

Answer 1

Solution:

The balanced chemical equation:

Br₂(g) + Cl₂(g) = 2BrCl(g)

ICE (Initial, Change, Equilibrium) table for this reaction:

[Br₂] = [Cl₂] = (0.2 - x) M

[BrCl] = (2x) M

The equilibrium constant expression K_c for the balanced equation:

7.20 = [2x / (0.2 - x)]²

2.6833 = 2x / (0.2-x)

2.6833 × (0.2 - x) = 2x

0.53666 - 2.6833x = 2x

0.53666 = 4.6833x

x = 0.1146

[Br₂] = [Cl₂] = 0.2 - x = 0.2 - 0.1146 = 0.0854 M

[BrCl] = 2x = (2 × 0.1146) = 0.2292 M

[BrCl] = 0.2292 M

Answer: The equilibrium concentration of BrCl is 0.2292 M.