Consider the reaction
PCl₅(g) $f$
PCl₃(g) + Cl₂(g)
At a certain temperature,If the initial concentration of PCl₅(g) Is 3.0 M,At equilibrium the concentration of Cl₂(g) Is 0.80 M.Calculate the value of K_c at this temperature.

Question

Consider the reaction
PCl₅(g)

f

PCl₃(g) + Cl₂(g)
At a certain temperature,If the initial concentration of PCl₅(g) Is 3.0 M,At equilibrium the concentration of Cl₂(g) Is 0.80 M.Calculate the value of K_c at this temperature.

Quizplus · Accepted Answer

The reaction is: $$PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g)$$Given initial $[PCl_5] = 3.0\ M$ and at equilibrium $[Cl_2] = 0.80\ M$, since the stoichiometry of the reaction is 1:1:1, the change in concentration of $PCl_5$ will be equal to the formation of $Cl_2$, which is $0.80\ M$. Therefore, the change in $PCl_5$ concentration is $-0.80\ M$, making its equilibrium concentration $3.0\ M - 0.80\ M = 2.2\ M$. The equilibrium concentration of $PCl_3$ will also be $0.80\ M$ because it forms in a 1:1 ratio with $Cl_2$.The equilibrium constant $K_c$ is given by:$$K_c = \frac{[PCl_3][Cl_2]}{[PCl_5]}$$Substituting the equilibrium concentrations:$$K_c = \frac{(0.80)(0.80)}{2.2} = \frac{0.64}{2.2} \approx 0.29$$

Consider the Reaction PCl5(g) fff PCl3(g)+ Cl2(g) at a Certain Temperature,If the Initial Concentration of Temperature,If

Consider the Reaction
PCl₅(g) $f$ PCl₃(g)+ Cl₂(g)
at a Certain Temperature,If the Initial Concentration of Temperature,If