Rate Constant Formula:
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Definition: This calculator determines the rate constant (K₂) at a higher temperature (T₂) based on the known rate constant (K₁) at a lower temperature (T₁) and the temperature coefficient (Φ).
Purpose: It helps chemists and chemical engineers predict reaction rates at different temperatures using the temperature coefficient.
The calculator uses the formula:
Where:
Explanation: The formula shows how the rate constant changes exponentially with temperature difference, scaled by the temperature coefficient.
Details: Accurate rate constant prediction is crucial for reaction engineering, process design, and understanding reaction kinetics at different temperatures.
Tips: Enter the known rate constant (K₁), temperature coefficient (default 1.25), and both temperatures (T₁ and T₂) in Kelvin. All values must be > 0.
Q1: What is a typical temperature coefficient value?
A: For many reactions, Φ is between 1.2 and 1.5, with 1.25 being a common default value.
Q2: Why is the temperature difference divided by 10?
A: The temperature coefficient is typically defined for a 10°C (or 10K) difference, so we scale accordingly.
Q3: How accurate is this calculation?
A: It provides a good estimate, but for precise work, use the Arrhenius equation with known activation energy.
Q4: Can I use Celsius instead of Kelvin?
A: No, you must use absolute temperature (Kelvin) as temperature differences are involved in the calculation.
Q5: What if my temperature coefficient is unknown?
A: You'll need experimental data at two temperatures to determine Φ before using this calculator.