Concentration of Radical formed during Chain Propagation Step given kw and kg Calculator

Formula Used:

\[ [R]_{CP} = \frac{k_1 \times [A]}{k_2 \times (1-\alpha) \times [A] + (k_w + k_g)} \]

Reaction Rate Constant for Initiation Step (k₁):

m³/mol·s

Concentration of Reactant A [A]:

mol/m³

Reaction Rate Constant for Propagation Step (k₂):

m³/mol·s

No. of Radicals Formed (α):

Rate Constant at Wall (k_w):

1/s

Rate Constant within Gaseous Phase (k_g):

1/s

Concentration of Radical [R] (mol/m³):

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1. What is Concentration of Radical formed during Chain Propagation Step?

Definition: This calculator determines the concentration of radicals formed during the chain propagation step in a chain reaction, considering both wall and gaseous phase rate constants.

Purpose: It helps chemical engineers and researchers understand and predict radical concentrations in chain reaction systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ [R]_{CP} = \frac{k_1 \times [A]}{k_2 \times (1-\alpha) \times [A] + (k_w + k_g)} \]

Where:

\( [R]_{CP} \) — Concentration of radical (mol/m³)
\( k_1 \) — Reaction rate constant for initiation step (m³/mol·s)
\( [A] \) — Concentration of reactant A (mol/m³)
\( k_2 \) — Reaction rate constant for propagation step (m³/mol·s)
\( \alpha \) — Number of radicals formed
\( k_w \) — Rate constant at wall (1/s)
\( k_g \) — Rate constant within gaseous phase (1/s)

Explanation: The formula accounts for radical formation, propagation, and termination (both at walls and in the gas phase).

3. Importance of Radical Concentration Calculation

Details: Understanding radical concentrations is crucial for controlling chain reactions, optimizing reaction conditions, and ensuring safety in chemical processes.

4. Using the Calculator

Tips: Enter all required parameters. Default values are provided for typical conditions. All rate constants must be positive, and α should be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the physical meaning of α?
A: α represents the number of radicals formed in each propagation step (typically 1-3 for most chain reactions).

Q2: How do I determine k₁ and k₂ experimentally?
A: These are typically determined through kinetic studies using techniques like flash photolysis or pulse radiolysis.

Q3: What factors affect k_w and k_g?
A: k_w depends on wall material and surface area, while k_g depends on gas composition, pressure, and temperature.

Q4: Why is radical concentration important?
A: Radical concentration directly affects reaction rate, product distribution, and potential for runaway reactions.

Q5: Can this be used for liquid phase reactions?
A: This specific formula is for gas-phase reactions. Liquid phase would require different termination terms.