Reversible and Irreversible chemical reactions

What is a reversible reaction?

• A reaction that can proceed in both the forward and reverse directions.
• A reaction that can only proceed in one direction.
• A reaction that cannot occur without a catalyst.
• A reaction where products can never reform the reactants.

Which of the following is a feature of an irreversible reaction?

• The reaction proceeds to completion.
• The reaction can proceed in both directions.
• Reactants and products are in dynamic equilibrium.
• The rate of the forward reaction equals the rate of the reverse reaction.

What does the position of equilibrium refer to in a reversible reaction?

• The relative concentrations of reactants and products at equilibrium.
• The physical location where the reaction occurs.
• The temperature at which the reaction is most efficient.
• The pressure needed to initiate the reaction.

In a closed system, when does a reversible reaction reach equilibrium?

• When the rate of the forward reaction equals the rate of the reverse reaction.
• As soon as the reactants are mixed together.
• When the temperature of the system is increased.
• When all reactants are used up.

What is Le Chatelier's principle?

• A system at equilibrium will respond to a disturbance by counteracting the change.
• The rate of a chemical reaction is directly proportional to the product of the reactant concentrations.
• The total energy in a closed system remains constant.
• The pressure and volume of a gas are inversely proportional at constant temperature.

What effect does an increase in temperature have on an exothermic reaction at equilibrium?

• Shifts the equilibrium towards the reactants.
• Shifts the equilibrium towards the products.
• Does not affect the equilibrium.
• Increases the rate of the reverse reaction only.

Which factor does not change the position of equilibrium in a chemical reaction?

• Presence of a catalyst.
• Change in concentration of reactants or products.
• Change in temperature.
• Change in pressure.

What is the equilibrium constant (Kc) an expression of?

• The ratio of product concentrations to reactant concentrations at equilibrium.
• The rate at which equilibrium is achieved.
• The maximum concentration of products that can be formed.
• The time it takes for a reaction to start.

Which statement about the equilibrium constant (Kc) is true?

• It is constant for a given reaction at a specific temperature.
• It increases as the concentration of reactants increases.
• It is a measure of how quickly equilibrium is reached.
• It changes with the addition of a catalyst.

Which type of reaction is typically associated with energy being released into the surroundings?

• Exothermic reactions.
• Endothermic reactions.
• Reversible reactions.
• Irreversible reactions.