Question

Consider the reaction below.

Answer 1

Answer:

• First choice: 0.042

Explanation:

Given decomposition reaction:

• 1PCl₅ (g) ⇄ 1PCl₃ + 1Cl₂(g)

Equilibrium constant:

• $K_{eq}=\frac{[PCl_3]^1[Cl_2]^1}{[PCl_5]^1}$

Stoichiometric coefficients and powers equal to 1 are not usually shown as they are understood, but I included them in order to shwow you how they intervene in the equilibrium expressions: each concentration is raised to a power equal to the respective stoichiometric coefficient in the equilibrium equation.

So, your calculations are:

$K_{eq}=\frac{(0.020M)(0.020M)}{0.0095M}=0.042M$