1. What is Rate Constant?

The rate constant (k) is a proportionality constant in the rate law of chemical kinetics that relates the reaction rate to the concentrations of reactants. It is temperature-dependent and follows the Arrhenius equation.

2. How Does the Calculator Work?

The calculator uses three main equations:

Where:

• \( k \) — Rate constant (s⁻¹)
• \( A \) — Pre-exponential factor (s⁻¹)
• \( Ea \) — Activation energy (J/mol)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Temperature (K)
• \( t_{1/2} \) — Half-life (s)

3. Importance of Rate Constants

Details: Rate constants are fundamental in chemical kinetics for determining reaction rates, predicting reaction behavior under different conditions, and designing chemical processes.

4. Using the Calculator

Tips: Select calculation type and enter required values. For Arrhenius equation, ensure temperature is in Kelvin and activation energy in kJ/mol.

5. Frequently Asked Questions (FAQ)

Q1: What are typical units for rate constants?
A: Units vary by reaction order. For first-order reactions: s⁻¹; second-order: M⁻¹s⁻¹; zero-order: M/s.

Q2: Why is the Arrhenius equation important?
A: It describes how rate constants change with temperature, crucial for understanding reaction kinetics.

Q3: What affects the pre-exponential factor?
A: It depends on collision frequency and orientation, affected by molecular size and complexity.

Q4: How does temperature affect rate constants?
A: Generally, increasing temperature increases rate constant exponentially (per Arrhenius equation).

Q5: What's the relationship between half-life and rate constant?
A: For first-order reactions, they are inversely related (t½ = ln(2)/k).