Chemical Equilibrium - Precision Quiz

Active Mass of Solid and Liquid Components The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• In the expression of the equilibrium constant, the active masses of pure solids and liquids are considered to be unity.

• The concentrations of pure solids and liquids directly influence the value of the equilibrium constant in a chemical reaction.

• For heterogeneous equilibria involving solids and liquids, their amounts do not appear in the equilibrium expression due to their constant active mass.

Dependence of Equilibrium on Temperature The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• The equilibrium position of an endothermic reaction shifts towards the products with an increase in temperature.

• A decrease in temperature will favor the exothermic direction of a reversible reaction, shifting its equilibrium position.

• The equilibrium constant for all reactions remains constant regardless of changes in temperature.

Role of Inert Gases in Equilibrium The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• Adding an inert gas to a reaction at constant volume does not change the equilibrium position because it does not affect the partial pressures of the reactants or products.

• Introduction of an inert gas into a closed system with movable piston, the partial pressures of reactants and products remain unaffected, thereby the equilibrium position is also unaffected.

• The addition of an inert gas at constant volume does not alter the equilibrium constant or the concentrations of reactants and products at equilibrium.

Impact of Concentration Changes on Equilibrium The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• Changing the concentration of reactants or products does not affect the equilibrium constant but will shift the position of the equilibrium.

• The equilibrium position shifts in the direction that tends to reduce the effect of the concentration change, in accordance with Le Chatelier's principle.

• An increase in the concentration of reactants always leads to a proportional increase in the equilibrium constant of the reaction.

Factors Affecting Equilibrium Constant The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• The equilibrium constant for a chemical reaction is unaffected by changes in pressure or volume of the system.

• Temperature is the only factor that can change the value of the equilibrium constant for a given reaction.

• Catalysts influence the equilibrium constant by altering the rate at which equilibrium is achieved.

Equilibrium in Heterogeneous Systems The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• The equilibrium expressions for heterogeneous reactions include the concentrations of gaseous and aqueous species but exclude pure solids and liquids.

• Heterogeneous equilibria involving solids and liquids are not influenced by changes in the solid or liquid phases.

• In heterogeneous equilibrium, the active masses of solids and liquids are assumed to change with temperature and pressure.

Chemical Equilibrium Fundamentals The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction, indicating dynamic but balanced activity.

• Equilibrium is achieved when the concentrations of reactants and products remain constant over time, even though reactions continue to occur at the molecular level.

• The state of equilibrium indicates the complete cessation of chemical reactions within the system.

Characteristics of Equilibrium The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• Chemical equilibrium is characterized by a dynamic state where the rates of the forward and reverse reactions are equal.

• Once a reaction mixture reaches equilibrium, the physical properties of the system, such as color and density, remain constant as long as the external conditions are unchanged.

• At chemical equilibrium, all reactions within the system stop and concentration remains unchanging

Equilibrium Constant Expression The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• The equilibrium constant for a reaction reflects the ratio of product concentrations to reactant concentrations at equilibrium, raised to the power of their stoichiometric coefficients.

• In a homogeneous reaction, the equilibrium constant expression may incorporate either concentrations or partial pressures of the reactants and products.

• The value of the equilibrium constant, Kc, changes with change in the initial concentrations of reactants and products, but not with their equilibrium concentrations.

Influence of Pressure on Gaseous Equilibrium The following three statements appear to convey the same idea or fact, but one statement is incorrect, identify the incorrect statement.

• An increase in the system's pressure, by reducing its volume, shifts the equilibrium of a gaseous reaction towards the side with fewer gaseous moles.

• The equilibrium position of a gaseous reaction is unaffected by changes in pressure if the number of moles of gas on both sides of the reaction is the same.

• For a gaseous reaction system, increasing the pressure always favors the formation of more products, regardless of the reaction stoichiometry.