A closed reaction vessel containing gaseous reactants and products is monitored
CHEMISTRY · Single correct · AP · Chemistry · Equilibrium · Equilibrium
Problem
A closed reaction vessel containing gaseous reactants and products is monitored, and a concentration–versus–time graph is obtained. The graph shows that, after about 120 s, the concentrations of all species remain constant with no further net change. Which of the following statements best explains what is occurring in the system after 120 s?
(a) Because the concentrations are flat, the amounts of reactants and products present must be equal.
(b) The forward and reverse reaction rates are equal, so the system is at dynamic equilibrium.
(c) The reaction has gone to completion, so all reactant molecules have been converted to products and no further reaction occurs.
(d) The forward reaction rate has dropped to zero, but the reverse reaction continues at a constant rate, keeping concentrations unchanged.