Chemical Equilibrium and Factors Affecting It

What is a reversible reaction?

• A reaction that only goes forward

• A reaction that can proceed in both forward and reverse directions

• A reaction that stops at equilibrium

• A reaction that only goes backward.

Fill in the blank: A reaction mixture must have certain characteristics to attain a state of chemical equilibrium, such as _______.

• Constant temperature

• Constant pressure

• Constant concentration of reactants and products

• Constant volume

Describe dynamic (chemical) equilibrium.

• A state where reactants are completely converted to products

• A state where the rate of the forward reaction equals the rate of the reverse reaction

• A state where no reactions occur

• A state where only the forward reaction occurs.

Relate the value of an equilibrium constant to the relative quantities of reactants and products at equilibrium.

• The equilibrium constant is always 1

• The equilibrium constant is unrelated to reactant and product quantities

• The equilibrium constant indicates the ratio of product to reactant concentrations at equilibrium

• The equilibrium constant is always greater than 1.

Write the chemical equilibrium expression for a homogeneous equilibrium system.

• Keq = [products]/[reactants]

• Keq = [reactants]/[products]

• Keq = [products] + [reactants]

• Keq = [reactants] - [products]

Calculate the value of the equilibrium constant given the concentration data at a specific equilibrium position.

• Use the formula Keq = [products]/[reactants]

• Use the formula Keq = [reactants]/[products]

• Use the formula Keq = [products] + [reactants]

• Use the formula Keq = [reactants] - [products]

Explain the effect of changing the concentration on an equilibrium system.

• It has no effect

• It shifts the equilibrium position

• It stops the reaction

• It reverses the reaction.

Explain the effect of changing the volume and pressure on an equilibrium system.

• It has no effect

• It shifts the equilibrium position

• It stops the reaction

• It reverses the reaction.

Apply Le Chatelier’s principle to predict the shift in equilibrium when the system is subjected to stress.

• The equilibrium will shift to oppose the change

• The equilibrium will remain unchanged

• The equilibrium will shift in the direction of the change

• The equilibrium will stop.

Fill in the blank: The chemical equilibrium expression for a heterogeneous equilibrium system is written as _______.

• Keq = [products]/[reactants]

• Keq = [reactants]/[products]

• Keq = [products] + [reactants]

• Keq = [reactants] - [products]