At equilibrium, the concentrations of reactants and products can be predicted us

Question

At equilibrium, the concentrations of reactants and products can be predicted using the equilibrium constant, Kc, which is a mathematical expression based on the chemical equation. For example, in the reaction

aA+bBcC+dD

where a, b, c, and d are the stoichiometric coefficients, the equilibrium constant is

where [A], [B], [C], and [D] are the equilibrium concentrations. If the reaction is not at equilibrium, the quantity can still be calculated, but it is called the reaction quotient, Qc, instead of the equilibrium constant, Kc.

Qc=[C]tc[D]td[A]ta[B]tb

where each concentration is measured at some arbitrary time t.

A mixture initially contains A, B, and C in the following concentrations: [A] = 0.700 M , [B] = 0.800 M, and [C] = 0.600 M . The following reaction occurs and equilibrium is established:

A+2BC

At equilibrium, [A] = 0.590 M and [C] = 0.710 M . Calculate the value of the equilibrium constant, Kc.

Explanation / Answer

In equilibrium

Initial

[A] = 0.70 - x = 0.59

[C] = 0.6 + x

x = 0.11

[B] = 0.8 - 2x = ??

0.8-2*.11 = 0.58

Solve

Kc = [C] / [A][B]^2 = 0.71 / (0.59*0.58^2) =3.57

Kc = 3.577

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.