Law of Mass Action

Chemistry ⇒ Chemical Kinetics and Equilibrium

Law of Mass Action starts at 11 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Law of Mass Action. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.

See sample questions for grade 12

Describe how the Law of Mass Action is used to derive the equilibrium constant expression for a general reaction.

Describe the difference between K_c and K_p in the context of the Law of Mass Action.

Describe the role of stoichiometric coefficients in the Law of Mass Action.

Explain why pure solids and pure liquids are not included in the equilibrium constant expression derived from the Law of Mass Action.

Explain why the Law of Mass Action does not apply to reactions in non-ideal solutions.

Explain why the Law of Mass Action is important in chemical equilibrium studies.

Explain why the Law of Mass Action is not valid for very concentrated solutions.

For the reaction 2A + B ⇌ 3C, write the equilibrium constant expression.

For the reaction 2A ⇌ B + C, if the equilibrium concentrations are [A] = 0.2 M, [B] = 0.1 M, and [C] = 0.1 M, calculate K_c.

For the reaction 2NO_2(g) \rightleftharpoons N_2O_4(g), if K_c = 4.0 at a certain temperature, and [NO_2] = 0.5 M, calculate [N_2O_4] at equilibrium.

For the reaction 2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g), write the equilibrium constant expression in terms of concentrations.

For the reaction 2X ⇌ Y + Z, if K_c = 0.5 and [X] = 0.4 M, [Y] = 0.1 M, calculate [Z] at equilibrium.

For the reaction A + B ⇌ C, if the initial concentrations are [A] = 1.0 M, [B] = 1.0 M, and at equilibrium [C] = 0.6 M, calculate K_c.

For the reaction A ⇌ B, if K_c = 2.0 and [A] = 0.5 M at equilibrium, what is [B]?

For the reaction aA + bB \rightleftharpoons cC + dD, write the expression for the equilibrium constant (K_c) according to the Law of Mass Action.

For the reaction aA + bB \rightleftharpoons cC, if the equilibrium concentrations are [A] = 1.0 M, [B] = 2.0 M, [C] = 3.0 M, a = 1, b = 2, c = 1, calculate K_c.

For the reaction H_2(g) + I_2(g) \rightleftharpoons 2HI(g), if [H_2] = 0.5 M, [I_2] = 0.5 M, and [HI] = 1.0 M at equilibrium, calculate K_c.

If the equilibrium constant (K_c) for a reaction is very large, what does it indicate about the position of equilibrium?

State the Law of Mass Action.

What is the effect of increasing the concentration of a reactant on the position of equilibrium, according to the Law of Mass Action?