Which of the following linear plots do you expect for a reaction A¡products if the kinetics are (a) zero order, [Section 14.4]

Verified step by step guidance

1. Identify the order of the reaction. For a zero-order reaction, the rate of reaction is independent of the concentration of the reactant.
2. Recall that for a zero-order reaction, the concentration of the reactant [A] decreases linearly over time.
3. Understand that the integrated rate law for a zero-order reaction is [A] = [A]_0 - kt, where [A]_0 is the initial concentration and k is the rate constant.
4. Recognize that a plot of [A] versus time will yield a straight line with a negative slope for a zero-order reaction.
5. Compare the given plots: Plot D shows [X] (which can be considered as [A]) versus time as a straight line, indicating a zero-order reaction.

Key Concepts

Zero-Order Kinetics

In zero-order kinetics, the rate of reaction is constant and independent of the concentration of the reactant. This means that the reaction proceeds at a steady rate until the reactant is depleted. The concentration of the reactant decreases linearly over time, leading to a plot of [A] versus time that is a straight line.

Integrated Rate Laws

Integrated rate laws relate the concentration of reactants to time for different orders of reactions. For zero-order reactions, the integrated rate law is [A] = [A]₀ - kt, where [A]₀ is the initial concentration, k is the rate constant, and t is time. This equation indicates that a plot of [A] versus time will yield a straight line, confirming zero-order behavior.

Graphical Representation of Reaction Orders

Different reaction orders produce distinct graphical representations when plotting concentration versus time or its transformations. For zero-order reactions, a plot of [A] versus time is linear, while plots of 1/[A] or ln[A] versus time are not linear. Understanding these graphical representations is crucial for identifying the order of a reaction based on experimental data.