In a closed reaction vessel the elementary reversible reaction A ⇌ B is occurring

CHEMISTRY · Multi-part · AP · Chemistry · Equilibrium · Equilibrium

Problem

In a closed reaction vessel the elementary reversible reaction A ⇌ B is occurring. At a particular instant the measured rates are Rateforward\text{Rate}_{\text{forward}} = 3.2×10−5 mol L−1 s−13.2\times10^{-5}\,\text{mol L}^{-1}\,\text{s}^{-1} Ratereverse\text{Rate}_{\text{reverse}} = 5.5×10−5 mol L−1 s−15.5\times10^{-5}\,\text{mol L}^{-1}\,\text{s}^{-1} Assume the reaction is the only process changing the concentrations of A and B. (1) Part 1: (a) Determine the direction of the net conversion at this instant, and calculate the numerical value of the net rate of change of B in mol L−1 s−1\text{mol L}^{-1}\,\text{s}^{-1}. (2) Part 2: (b) State the sign (positive, negative, or zero) of d[A]dt\dfrac{d[\text{A}]}{dt} and of d[B]dt\dfrac{d[\text{B}]}{dt} at this instant. Justify each sign in terms of the rates supplied. (3) Part 3: (c) Describe what must happen to the magnitudes of Rateforward\text{Rate}_{\text{forward}} and Ratereverse\text{Rate}_{\text{reverse}} as time proceeds if the system is to reach equilibrium. Explain why this does not require the concentrations of A and B to become equal.

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