1. What is Activation Energy?

Activation energy (Ea) is the minimum energy required for a chemical reaction to occur. It represents the energy barrier that must be overcome for reactants to transform into products.

2. How to Determine Ea from Graph

The Arrhenius equation relates reaction rate constants to temperature:

Where:

• \( k \) — Reaction rate constant
• \( E_a \) — Activation energy (J/mol)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Absolute temperature (K)
• \( A \) — Pre-exponential factor

Graph Method: Plot ln k vs 1/T (inverse temperature). The slope of the resulting line equals -Ea/R.

3. Importance of Activation Energy

Details: Activation energy helps predict reaction rates at different temperatures and provides insight into reaction mechanisms. Lower Ea means faster reaction at given temperature.

4. Using the Calculator

Steps:

1. Measure rate constants (k) at several temperatures
2. Plot ln k vs 1/T (K⁻¹)
3. Determine the slope of the best-fit line
4. Enter the slope value in the calculator

5. Frequently Asked Questions (FAQ)

Q1: What units should the slope be in?
A: The slope should be in Kelvin (K) units from your ln k vs 1/T plot.

Q2: How many data points are needed?
A: At least 3-5 temperature points are recommended for accurate slope determination.

Q3: What if my graph isn't linear?
A: Non-linearity may indicate experimental error or that the reaction doesn't follow simple Arrhenius behavior.

Q4: Can I use different temperature units?
A: No, temperature must be in Kelvin for the Arrhenius plot.

Q5: What's the typical range for Ea values?
A: Most reactions have Ea between 50-250 kJ/mol, though some can be outside this range.