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Zero-Order Reaction

rate = k
Quick Reference
Formula / Notationrate = k
Also Known AsZero-order kinetics, zero-order rate law, concentration-independent reaction

What is Zero-Order Reaction?

A zero-order reaction is a reaction whose rate is independent of the concentration of the reactant(s). The rate is constant and equal only to the rate constant k. This occurs when a reaction is limited by something other than reactant concentration, such as catalyst surface area, enzyme concentration (when fully saturated), or light intensity. As the reaction proceeds, concentration decreases linearly with time.

Formula & Notation

rate = k

Other Names / Synonyms: Zero-order kinetics, zero-order rate law, concentration-independent reaction

Properties & Characteristics

Rate = k (constant, independent of [A]). Integrated rate law: [A]t = [A]₀ − kt. Linear plot: [A] vs. t. Half-life: t₁/₂ = [A]₀ / (2k) — decreases as reaction proceeds. Units of k: mol/L·s. Examples: surface-catalyzed reactions at saturation, enzyme-catalyzed reactions (Michaelis-Menten at high substrate).

Uses & Applications

Understanding enzyme kinetics (Vmax in Michaelis-Menten = zero-order). Drug release from controlled-release formulations. Heterogeneous catalysis analysis. Surface reaction kinetics. Pharmaceutical dosing calculations.

Safety Information

Conceptual classification — safety depends on specific reaction. Zero-order reactions may proceed at a constant rate even as reactant is depleted — important consideration in industrial reactor safety.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Zero-Order Reaction
Formula rate = k
Synonyms Zero-order kinetics, zero-order rate law, concentration-independent reaction

Frequently Asked Questions

A zero-order reaction is a reaction whose rate is independent of the concentration of the reactant(s). The rate is constant and equal only to the rate constant k. This occurs when a reaction is limited by something other than reactant concentration, such as catalyst surface area, enzyme concentration (when fully saturated), or light intensity. As the reaction proceeds, concentration decreases linearly with time.

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