First-order Rate Law Calculator
🔥 Thermochemistry & Bonding. Use the First-order rate law formula to find rate, rate constant k, [a]: pick the value you want, type the others, and the answer updates as you go.
Rate0.002 mol/(L·s)
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Rate | mol/(L·s) |
| Rate constant k | 1/s |
| [A] | mol/L |
Worked example
Find the rate when Rate constant k = 0.02 1/s, [A] = 0.1 mol/L.
Using -d[A]/dt = k[A]: Rate = 0.002 mol/(L·s).
Frequently asked questions
What is the formula for First-order rate law?
-d[A]/dt = k[A].
What do the letters stand for, and what units are used?
Rate in mol/(L·s), Rate constant k in 1/s, [A] in mol/L.
How do you calculate rate?
Put the values into -d[A]/dt = k[A]. For example, with Rate constant k = 0.02 1/s, [A] = 0.1 mol/L, rate = 0.002 mol/(L·s).
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (rate, rate constant k, [a]) and fill in the others: it rearranges the formula for you.
