Explore the Reaction Mechanism & Rate-Determining Step
See a two-step mechanism as an energy profile, drag the peaks and find the slowest step and rate law. Free, no signup, runs in your browser.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The Reaction Mechanism & Rate-Determining Step with sample data entered and the result showing.
What is the Reaction Mechanism & Rate-Determining Step?
See a two-step mechanism as an energy profile, drag the peaks and find the slowest step and rate law. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
Chemists study mechanisms to design faster catalysts, make drugs more efficiently and understand ozone depletion.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Many reactions happen in several elementary steps.
The step with the biggest barrier is the rate-determining step.
The rate law comes from the slow step.
Drag TS₁ above TS₂, then the reverse, and watch the slow step change.
Play the ball through the SN1 mechanism.
Read the rate law of each mechanism.
Used for
Pick one to see how it fits.
Reactions & Kinetics learners
Students learning reaction rates, equilibrium and equations, and teachers who want a visual way to explain what happens to particles.
Try it freeTeachers
For teachers: project the Reaction Mechanism & Rate-Determining Step on the board, let students predict the result, then run it together and test this: Play the ball through the SN1 mechanism. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
What is the rate-determining step?
The slowest elementary step. It limits how fast the overall reaction can go.
What is the difference between an intermediate and a transition state?
An intermediate is a real species in an energy valley; a transition state is the unstable peak between species.
Is the Reaction Mechanism & Rate-Determining Step free to use?
Yes. The Reaction Mechanism & Rate-Determining Step is free, needs no signup or download and runs in your web browser. It is part of the Reactions & Kinetics group of AZRS simulations.
Does the Reaction Mechanism & Rate-Determining Step work on a phone or tablet?
Yes. The Reaction Mechanism & Rate-Determining Step takes touch input as well as mouse input, so you can use its 1 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
How do I use the Reaction Mechanism & Rate-Determining Step?
1. In the Reaction Mechanism & Rate-Determining Step, use the controls to change Mechanism. The simulation reacts instantly. 2. In the Reaction Mechanism & Rate-Determining Step, pick an option such as SN1 (2 steps), NO₂ + CO, Ozone + Cl catalyst, Custom to switch modes or load an example. 3. In the Reaction Mechanism & Rate-Determining Step, press "Play reaction" to start, reset or change what is happening. 4. Start with this experiment: Drag TS₁ above TS₂, then the reverse, and watch the slow step change. Drag any glowing handle, object or slider with your mouse or finger and the Reaction Mechanism & Rate-Determining Step responds in real time. 5. Change one setting at a time and watch which readout moves, then compare it with this idea: Many reactions happen in several elementary steps.
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Try the Reaction Mechanism & Rate-Determining Step now
See a two-step mechanism as an energy profile, drag the peaks and find the slowest step. Free to use.
Try it free