Intermediate Concentration for Zero Order followed by First Order with Less Rxn Time Calculator

Formula Used:

\[ C_R = \frac{C_{A0}}{K} \times (1 - e^{-(k_1 \times \Delta t')}) \]

Initial Concentration of Reactant (CA0):

mol/m³

Overall Rate of Reaction (K):

mol/(m³·s)

Rate Constant for 1st Order 2nd Step (k1):

mol/(m³·s)

Time Interval (Δt'):

seconds

Intermediate Concentration (CR): mol/m³

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Intermediate Concentration for Zero Order followed by First Order?

Definition: This calculator determines the intermediate concentration in a series reaction where the first step follows zero-order kinetics and the second step follows first-order kinetics.

Purpose: It helps chemical engineers and researchers analyze reaction kinetics and predict intermediate product concentrations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ C_R = \frac{C_{A0}}{K} \times (1 - e^{-(k_1 \times \Delta t')}) \]

Where:

\( C_R \) — Intermediate concentration (mol/m³)
\( C_{A0} \) — Initial reactant concentration (mol/m³)
\( K \) — Overall rate of reaction (mol/(m³·s))
\( k_1 \) — First-order rate constant (mol/(m³·s))
\( \Delta t' \) — Time interval (seconds)

Explanation: The formula accounts for the exponential decay of reactant concentration over time in a two-step reaction series.

3. Importance of Intermediate Concentration Calculation

Details: Accurate calculation of intermediate concentrations is crucial for reaction optimization, process control, and understanding reaction mechanisms.

4. Using the Calculator

Tips: Enter the initial reactant concentration, overall rate of reaction (default 1.593), first-order rate constant (default 0.07), and time interval (default 2.99 seconds). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does a zero-order followed by first-order reaction mean?
A: It describes a two-step reaction where the first step's rate is independent of concentration (zero-order), and the second step's rate depends linearly on concentration (first-order).

Q2: When is this calculation most useful?
A: For analyzing reaction kinetics in series reactions, especially in pharmaceutical and polymer chemistry.

Q3: How do I determine the rate constants?
A: Rate constants are typically determined experimentally through kinetic studies.

Q4: What units should I use?
A: Consistent SI units are recommended (mol/m³ for concentrations, seconds for time).

Q5: Can this be used for other reaction orders?
A: No, this specific formula applies only to zero-order followed by first-order series reactions.