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Chapter 14: Problem 15

One of the following statements is true and the other is false regarding the first-order reaction 2A \(\longrightarrow \mathrm{B}+\mathrm{C}\). Identify the true statement and the false one, and explain your reasoning. (a) The rate of the reaction decreases as more and more of \(\mathrm{B}\) and \(\mathrm{C}\) form. (b) The time required for one-half of substance \(A\) to react is directly proportional to the quantity of A present initially.

Short Answer

Expert verified
Both statements (a) and (b) are false. The rate of a first-order reaction does not change with the formation of products, and the half-life of a first-order reaction is constant and not dependent on the initial concentration of the reactant.

Step by step solution

01

Check Statement (a)

The rate of a first-order reaction is dependent only on the concentration of one reactant, in this case, A. It does not change with the formation of products B and C. Therefore, as long as there is reactant A remaining, the rate of the reaction remains constant, assuming the temperature remains constant. Hence, statement (a) that suggests the rate of reaction decreases as more B and C form is false.
02

Check Statement (b)

The time required for half of the reactant A to react (half-life) in a first order reaction is a constant that is independent of the initial concentration of A. Therefore, regardless of how much A is present at the start, the half-life remains the same. Hence, statement (b), stating that the time required for one-half of A to react is directly proportional to the quantity of A present initially, is also false.

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Most popular questions from this chapter

Explain the important distinctions between each pair of terms: (a) first-order and second-order reactions; (b) rate law and integrated rate law; (c) activation energy and enthalpy of reaction; (d) elementary process and overall reaction; (e) enzyme and substrate.

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