1. What is the Arrhenius Equation?

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

2. How Does the Calculator Work?

The calculator uses the Arrhenius equation:

Where:

• \( Ea \) — Activation energy (J/mol)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( k1 \) — Rate constant at temperature T1
• \( k2 \) — Rate constant at temperature T2
• \( T1 \) — First absolute temperature (Kelvin)
• \( T2 \) — Second absolute temperature (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 required 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 (k1, k2) and their corresponding absolute temperatures in Kelvin (K). All values must be positive and T1 ≠ T2.

5. Frequently Asked Questions (FAQ)

Q1: What units should be used for temperature?
A: Temperatures must be in absolute Kelvin (K). Convert Celsius to Kelvin by adding 273.15.

Q2: Can I use different units for rate constants?
A: The units can be any consistent measure (s⁻¹, M⁻¹s⁻¹, etc.), but k1 and k2 must have the same units.

Q3: What are typical activation energy values?
A: Most chemical reactions have Ea between 50-250 kJ/mol, though biological reactions are often lower.

Q4: Why must T1 and T2 be different?
A: The calculation requires a temperature difference to determine how the rate changes with temperature.

Q5: How accurate is this method?
A: For best results, measure rates at several temperatures and use linear regression of ln(k) vs 1/T.