Answer:
The correct answer is 8.10
Explanation:
Given:
A(g) + 2B(g) ↔ AB₂(g) Kc = 59 ---- Eq. 1
A(g) + 3B(g) ↔ AB₃(g) Kc = 478 ----- Eq. 2
We have to rearrange the chemical equations in order to obtain:
AB₂(g) + B(g) ↔ AB₃(g) Kc = ?
AB₂(g) is a reactant, so we have to use the reverse reaction of Eq. 1, in this case Kc= 1/59. Since AB₃(g) is a product, we use the forward reaction of Eq.2, and the constant is the same: Kc= 478. The following is the sum of rearranged chemical equations, and the compounds in bold and italic are canceled:
AB₂(g) ↔ <em>A(g)</em> + <em>2B(g)</em> Kc₁= 1/59
<em>A(g)</em> + <em>3B(g)</em> ↔ AB₃(g) Kc₂= 478
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AB₂(g) + B(g) ↔ AB₃(g)
If we add reactions at equilibrium, the equilibrium constants Kc are mutiplied as follows:
Kc = Kc₁ x Kc₂ = 1/59 x 478 = 478/59 = 8.10
The value of the missing equilibrium constant is 8.10.
