1. What is the Arrhenius Equation?

The Arrhenius equation describes the temperature dependence of reaction rates. The two-point form calculates activation energy (Ea) from rate constants at two different temperatures.

2. How Does the Calculator Work?

The calculator uses the two-point Arrhenius equation:

Where:

• \( Ea \) — Activation energy (J/mol)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( k_1, k_2 \) — Rate constants at temperatures T₁ and T₂ (1/s)
• \( T_1, T_2 \) — Absolute temperatures (Kelvin)

Explanation: The equation relates the natural logarithm of the rate constant ratio to the inverse temperature difference.

3. Importance of Activation Energy

Details: Activation energy represents the minimum energy needed for a chemical reaction to occur. It helps predict reaction rates at different temperatures and understand reaction mechanisms.

4. Using the Calculator

Tips: Enter rate constants in 1/s and temperatures in Kelvin. All values must be positive, and temperatures must be different.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use?
A: Rate constants in 1/s, temperatures in Kelvin. The result is in J/mol (divide by 1000 for kJ/mol).

Q2: Why must temperatures be different?
A: The denominator would be zero with identical temperatures, making the equation undefined.

Q3: What's a typical range for Ea?
A: Most reactions have Ea between 50-250 kJ/mol (50,000-250,000 J/mol).

Q4: Can I use Celsius temperatures?
A: No, you must convert to Kelvin first (K = °C + 273.15).

Q5: How accurate is this method?
A: For precise results, measure rate constants at multiple temperatures and perform linear regression on an Arrhenius plot.