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· Last updated：2026-07-27
Fit zero-order, first-order, and second-order rate equations to concentration-time data. Get reaction order, rate constant k, half-life t½, and R² goodness-of-fit.
Details
Enter your experimental concentration-vs-time data points and the tool fits all three integrated rate laws in parallel: zero-order ([A] vs t), first-order (ln[A] vs t), and second-order (1/[A] vs t). It reports each model's rate constant k, the linearization R², and the half-life, then identifies which order best fits your data (highest R²). Ideal for general-chemistry kinetics labs where you need to determine the reaction order from experimental data.
Execution
Fill in the form, run the tool, and review the result in one place.
Samples
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Tool usage guide
The Reaction Rate Calculator fits zero-order, first-order, and second-order rate equations to concentration-time data, then reports the reaction order, rate constant k, half-life, and R² goodness-of-fit for each model.
Background
A student measures a concentration that halves every 100 seconds.
Problem
They need to determine the reaction order and calculate k and the half-life.
How to use
Enter the time and concentration pairs one per line: 0, 1.000; 100, 0.500; 200, 0.250; 300, 0.125; 400, 0.0625.
Outcome
The calculator identifies first-order kinetics with R² close to 1.0, k approximately 0.00693 s⁻¹, and a half-life of 100 s.
Background
A concentration dataset shows a reciprocal concentration that increases approximately linearly over time.
Problem
The researcher wants to distinguish second-order kinetics from zero- and first-order behavior.
How to use
Enter 0, 1.0; 100, 0.5; 200, 0.333; 300, 0.25; 400, 0.2, with one pair on each line.
Outcome
The calculator compares all three rate-law fits and identifies second-order kinetics based on the highest R², while reporting its k and half-life.
Enter concentration-time pairs, with one pair per line, such as 0, 1.000.
It tests zero-order, first-order, and second-order rate laws.
The calculator selects the model with the highest linearization R².
It reports reaction order, rate constant k, half-life, and R² for the fitted models.
Yes. Enter your measured concentration-time points in the required one-pair-per-line format.