Overall Reaction Order Calculator

Calculate kinetic orders using three measured experiments. See constants, predictions, and graph outputs instantly. Learn reaction trends with guided chemistry steps.

Calculator Input

Enter three experimental trials. The calculator solves the reactant orders and the total order from the measured rate data.

Plotly Graph

The chart compares measured rates, predicted rates, and calculated orders.

Example Data Table

Experiment [A] [B] Rate Interpretation
1 0.10 0.10 0.020 Baseline trial
2 0.20 0.10 0.080 Doubling A quadruples rate
3 0.20 0.20 0.160 Doubling B doubles rate

Formula Used

Rate = k[A]x[B]y

The overall reaction order equals the sum of all partial orders. For two reactants, total order = x + y.

Using experiment ratios removes k. The calculator solves these logarithmic equations:

ln(Rate2/Rate1) = x ln([A]2/[A]1) + y ln([B]2/[B]1)

ln(Rate3/Rate1) = x ln([A]3/[A]1) + y ln([B]3/[B]1)

After solving x and y, the tool estimates k from each experiment and reports the average value.

How to Use This Calculator

  1. Enter labels for both reactants and the rate term.
  2. Provide concentration and rate values for three experiments.
  3. Use positive numbers only.
  4. Ensure experiments vary independently for a solvable system.
  5. Click the calculate button.
  6. Review partial orders, total order, and rate constant.
  7. Inspect predicted rates and percentage errors.
  8. Download the results as CSV or PDF.

FAQs

1. What is overall reaction order?

Overall reaction order is the sum of the exponents in the rate law. It describes how the total reaction rate changes when all reactant concentrations change.

2. Why are three experiments used here?

Three experiments provide enough information to solve for two unknown reactant orders and then verify the fit using a third data point and predicted rates.

3. Can this calculator handle zero values?

No. Concentrations and rates must be positive because the method uses logarithms. Zero or negative values make the logarithmic equations undefined.

4. What does a fractional order mean?

A fractional order shows that the rate does not change by a simple whole-number pattern. It often appears in complex mechanisms or multistep reactions.

5. Why might the system be unsolvable?

If the experiments do not vary concentrations independently, the equations become dependent. Then the determinant becomes zero and unique orders cannot be found.

6. What is the role of the rate constant k?

The rate constant scales the entire rate law. After the orders are found, k is computed from each experiment and averaged for a representative value.

7. Why are predicted rates shown?

Predicted rates help you compare the fitted rate law with measured data. Small errors suggest the experimental model matches the entered kinetics well.

8. Can I use different units?

Yes. Use any consistent concentration and rate units. The computed orders remain unchanged, though the numerical value and units of k may differ.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.