Concepts of Chemical Equilibrium

Which of the following is true for a chemical reaction at equilibrium?

• only the forward reaction stops
• only the reverse reaction stops
• the rates of the forward and reverse reactions are equal
• the rate constants for the forward and reverse reactions are equal

Which of the following is true regarding the concentration of products, for a chemical reaction that is already at equilibrium, assuming no disruptions to the equilibrium?

• The concentrations of products will not change because the forward and reverse rates are equal
• The concentrations of products will not change because there are no more reactants.
• The concentrations of products will not change because the limiting reagent is gone
• The concentrations of products will change continually because of reversibility

A chemical equilibrium may be established by starting a reaction with __________

•  reactants only.
• products only
• any quantities of reactants and products.
• all the above

An equilibrium that strongly favors products has __________

• a value of K << 1
• a value of K >> 1.
• a value of Q >> 1.
• a value of Q << 1.

If the reaction quotient Q has a smaller value than the related equilibrium constant, K, __________

• the reaction is not at equilibrium, and will make more products at the expense of reactants.
• the reaction is at equilibrium.
• the reaction is not at equilibrium, and will make more reactants at the expense of products.
• the value of K will decrease until it is equal to Q

Which of the following occurs when reactants are added to a chemical reaction in solution or the gas phase at equilibrium?

• Q increases, so the equilibrium shifts to produce more products.
• Q increases, so the equilibrium shifts to produce more reactants.
• Q decreases, so the equilibrium shifts to produce more products.
• Q decreases, so the equilibrium shifts to produce more reactants.

Increasing the temperature of an endothermic reaction results in __________ 

• more products and fewer reactants.
• more reactants and fewer products.
• no change in the quantities of reactants and products.
• fewer reactants and products.