Backward Reaction Rate Constant given Keq and kf Calculator

Formula Used:

\[ k_{b}' = K_{eq} \times k_{f}' \]

Backward Reaction Rate Constant (kb'):

m³/(mol·s)

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1. What is Backward Reaction Rate Constant given Keq and kf?

Definition: This calculator determines the backward reaction rate constant (kb') for a 2nd order reaction using the equilibrium constant (Keq) and forward reaction rate constant (kf').

Purpose: It helps chemists and chemical engineers calculate the rate constant for the reverse reaction when the equilibrium constant and forward rate constant are known.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ k_{b}' = K_{eq} \times k_{f}' \]

Where:

\( k_{b}' \) — Backward reaction rate constant (m³/(mol·s))
\( K_{eq} \) — Equilibrium constant of the reaction
\( k_{f}' \) — Forward reaction rate constant (m³/(mol·s))

Explanation: At equilibrium, the ratio of forward to backward rate constants equals the equilibrium constant. This relationship allows calculation of one rate constant when the other and Keq are known.

3. Importance of Reaction Rate Constants

Details: Reaction rate constants are fundamental to chemical kinetics, helping predict reaction rates and design chemical processes.

4. Using the Calculator

Tips: Enter the equilibrium constant (Keq) and forward reaction rate constant (kf') in the appropriate fields. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use for the rate constants?
A: For 2nd order reactions, the units should be in m³/(mol·s). Ensure consistent units for accurate results.

Q2: Does this formula work for all reaction orders?
A: This specific formula applies to 2nd order reactions. Different orders require different relationships between rate constants.

Q3: How is the equilibrium constant related to rate constants?
A: At equilibrium, Keq = kf'/kb' for elementary reactions, hence kb' = kf'/Keq.

Q4: Can I use this for gas-phase reactions?
A: Yes, but ensure your rate constants and equilibrium constant are in consistent units (pressure or concentration basis).

Q5: What if my reaction isn't elementary?
A: For complex reactions, this relationship might not hold directly, and you may need to consider the reaction mechanism.