The equilibrium constant of concentration (Kc) expresses the ratio of concentrations #[ C ]# of products over reactants for a reaction that is at equilibrium.
#2 ICl rightleftharpoons# #"Cl_2 + I_2#
The equilibrium constant is written as:
#K_C# = #([I_2] [Cl_2])/([ICl]^2)#
#"If :"#
#K_C>1# #=># #"equilibrium favors Products"#
#K_C<1# #=># #"equilibrium favors the Reactants"#
#underline"DATA"#
#[ICl]_0# = #"0.682 g" /"162.357 (g/mol)"##"= 0.00420 mol"#
#"Molarity"-> [ICl]_0# = #"0.0042 mol" /"0.765 (L)"##= 0.00549 M #
#[I_2]_E# = #"0.0383 g" /"253.808(g/mol)"##"= 0.000151 mol"#
#"Molarity"-> [I_2]_E# = #"0.000151 mol" /"0.765 (L)"##= 0.000197 M # = #[Cl_2]_E#
#underline"CONC. AT EQUILIBRIUM"#
#[ICl]_E# = #[ICl]_0# - #[I_2]_E#. - #[Cl_2]_E# = 0.00549 - 2(0.000197) =
#0.005096# M
SUBSTITUTING DATA IN #K_C#
#K_C# = #([0.000197] [0.000197])/([0.005096]^2)#= #color(blue)0.00149#