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For the reaction 2 A + B <--> C, the equilibrium concentrations are found to be: [A] = 1.8 X 10^-2 M, [B] = 2.4 X 10^-3 M, and [C] = 5.3 X 10^-4 M. What is the value of Keq?

Answer 1

Peyton Adams

#K_"eq"~=7xx10^2#

We gots the equilibrium...#2A+BrightleftharpoonsC#...

...and we write the equilibrium expression as...

#K_"eq"=([C])/([A]^2[B])#, where #[A]#, #[B]#, and #[C]# are the concentrations AT EQUILIBRIUM.

But the boundary conditions of the problem gives us PRECISELY those concentrations...

#K_"eq"=([C])/([A]^2[B])=(5.3xx10^-4)/((1.8xx10^-2)^2(2.4xx10^-3))=681.6#..

So which side is favoured at equilibrium, products or reactants?

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

For the reaction 2 A + B &lt;--&gt; C, the equilibrium concentrations are found to be: [A] = 1.8 X 10^-2 M, [B] = 2.4 X 10^-3 M, and [C] = 5.3 X 10^-4 M. What is the value of Keq?

For the reaction 2 A + B <--> C, the equilibrium concentrations are found to be: [A] = 1.8 X 10^-2 M, [B] = 2.4 X 10^-3 M, and [C] = 5.3 X 10^-4 M. What is the value of Keq?