1. What is Activation Energy?

Definition: Activation Energy is the minimum amount of energy required to activate atoms or molecules to a condition where they can undergo chemical transformation.

Purpose: This calculator determines activation energy from the slope of an Arrhenius plot (ln K vs 1/T).

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( E_a \) — Activation Energy (J/mol)
• Slope — Slope from ln K vs 1/T plot (Kelvin)
• \( R \) — Universal gas constant (8.314 J/mol·K)

Explanation: The negative slope of an Arrhenius plot multiplied by the gas constant gives the activation energy.

3. Importance of Activation Energy

Details: Activation energy determines reaction rates and temperature dependence. Lower activation energy means faster reactions.

4. Using the Calculator

Tips: Enter the slope obtained from plotting ln(rate constant) vs 1/temperature (in Kelvin). The slope should be negative for most reactions.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for activation energies?
A: Most chemical reactions have activation energies between 50-250 kJ/mol (50,000-250,000 J/mol).

Q2: Why is the slope negative in Arrhenius plots?
A: Because reaction rates increase with temperature, giving a negative relationship between ln K and 1/T.

Q3: What units should the slope be in?
A: The slope should be in Kelvin (K) since it's from a plot of ln K (unitless) vs 1/T (1/Kelvin).

Q4: Can this be used for biological systems?
A: Yes, the Arrhenius equation applies to enzyme-catalyzed reactions, though with some limitations.

Q5: How accurate is this calculation?
A: It's mathematically exact, but accuracy depends on precise measurement of the slope from your experimental data.