A reaction between A and 2 B produces products by the stoichiometric equation Kinetic…

CHEMISTRY · Multi-part · A Level · Chemistry · Rate equations · Rate equations

Problem

A reaction between A and 2 B produces products by the stoichiometric equation A+2B→productsA + 2B \rightarrow \text{products} Kinetic experiments at 310 K yield the rate law rate=k[A][B]\text{rate} = k[A][B] (overall order = 2) Assume the reaction takes place in a closed, constant-volume vessel that initially contains [A]0=[B]0=0.50 M[A]_0 = [B]_0 = 0.50\,\text{M} and no products. (1) Part 1: Derive an expression for the concentration of A as a function of time, starting from the differential rate law. Clearly state any mathematical steps used in your derivation. (2) Part 2: From your integrated expression, obtain a formula for the half-life t1/2t_{1/2} in terms of the initial concentration [A]0[A]_0 and the rate constant kk. (3) Part 3: Compare the dependence of half-life on initial concentration for this second-order reaction with that of a first-order reaction. Explain how experimental measurement of half-life versus initial concentration could be used to confirm the overall reaction order. (4) Part 4: If k=2.0×102 M−1 s−1k = 2.0 \times 10^{2}\,\text{M}^{-1}\,\text{s}^{-1}, calculate the time required for [A][A] to decrease to 0.10 M0.10\,\text{M} under the stated initial conditions.

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