Reaction Calculator
Formula Used
Integrated first order law: Ct = C0 × e-kt
Rate constant from data: k = ln(C0 / Ct) / t
Elapsed time: t = ln(C0 / Ct) / k
Half life: t1/2 = ln(2) / k
First order reactions decay at a rate proportional to the current concentration. A constant fraction reacts during equal time intervals. This behavior is common in decomposition, radioactive decay models, and many solution kinetics studies.
How to Use This Calculator
- Select the calculation mode based on your unknown value.
- Enter the initial concentration and any known kinetic values.
- Keep units consistent for time, concentration, and temperature notes.
- Press Calculate Reaction to display results above the form.
- Download the calculated summary as a CSV or PDF file.
Example Data Table
| Example | C0 | Ct | k | t | Half Life | Comment |
|---|---|---|---|---|---|---|
| Hydrolysis Run A | 1.000 mol/L | 0.500 mol/L | 0.0693 min⁻¹ | 10 min | 10 min | Half concentration after one half life. |
| Decomposition Run B | 0.800 mol/L | 0.200 mol/L | 0.1386 min⁻¹ | 10 min | 5 min | Quarter concentration after two half lives. |
| Lab Practice Run | 2.000 mol/L | 0.736 mol/L | 0.2000 h⁻¹ | 5 h | 3.466 h | Useful for checking manual calculations. |
Concentration Decay Chart
The chart uses the active rate constant and initial concentration. Calculate once to refresh the plotted decay path.