1. What is a First-Order Reaction?

A first-order reaction is a chemical reaction where the rate depends linearly on the concentration of one reactant. The rate law for a first-order reaction is given by Rate = k[A], where k is the rate constant and [A] is the concentration of the reactant.

2. How Does the Calculator Work?

The calculator uses the first-order reaction rate equation:

Where:

• \( k \) — Rate constant (1/s)
• \( [A] \) — Concentration of reactant A (M)
• Rate — Reaction rate (mol/s)

Explanation: The reaction rate is directly proportional to the concentration of the reactant. The rate constant k determines how fast the reaction proceeds at a given concentration.

3. Importance of Reaction Rate Calculation

Details: Understanding reaction rates is crucial for chemical kinetics, reaction engineering, and predicting how long a reaction will take to complete. First-order reactions are common in nature, including radioactive decay and many biological processes.

4. Using the Calculator

Tips: Enter the rate constant in 1/s and the concentration in molarity (M). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical units for first-order rate constants?
A: The units are reciprocal seconds (1/s or s⁻¹) for first-order reactions.

Q2: How does temperature affect the rate constant?
A: According to the Arrhenius equation, the rate constant increases exponentially with temperature.

Q3: What's the half-life of a first-order reaction?
A: The half-life (t₁/₂) is constant and calculated as ln(2)/k, independent of initial concentration.

Q4: Are there real-world examples of first-order reactions?
A: Yes, including radioactive decay, many enzyme-catalyzed reactions, and some decomposition reactions.

Q5: How is this different from zero-order or second-order reactions?
A: Zero-order rates are constant (independent of concentration), while second-order rates depend on concentration squared or product of two concentrations.