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Concept module

Dynamic Equilibrium / Le Chatelier's Principle

Watch a reversible chemistry bench keep changing microscopically while the mixture settles toward a new balance after each disturbance.

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Starter track

Step 2 of 20 / 2 complete

Rates and Equilibrium

Earlier steps still set up Dynamic Equilibrium / Le Chatelier's Principle.

1. Reaction Rate / Collision Theory2. Dynamic Equilibrium / Le Chatelier's Principle

Previous step: Reaction Rate / Collision Theory.

Start from track beginning

Why it behaves this way

Explanation

Dynamic equilibrium becomes easier to trust when the particles keep changing even after the mixture looks settled. This module keeps reactants, products, forward change, reverse change, and the time path toward a new balance on one shared chemistry bench.

The main idea is that equilibrium does not mean stopped. It means the forward and reverse changes have become equally strong, so the visible mixture can stay steady even though the microscopic swapping keeps going.

Key ideas

01At dynamic equilibrium, forward and reverse changes are still happening, but they balance each other.
02Changing the mixture or the product-favor conditions disturbs the balance and sends the system toward a new equilibrium.
03Le Chatelier's principle is easiest to trust when the disturbance and the re-balancing path stay visible together.

Frozen walkthrough

Step through the frozen example

Frozen walkthrough
Use the current chemistry bench instead of a detached table. The same controls drive the particle scene, the time history, and these substitutions.

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Frozen valuesUsing frozen parameters

At the current time, what is the balance between forward and reverse change?

Time

0

Starting reactant amount

14

Starting product amount

4

1. Read the current mixture

At t = 0 s, the bench shows about 14 reactant units and 4 product units.

2. Read the competing rates

The forward rate is about 3.14/s while the reverse rate is about 0.71/s.

3. Read how close the system is to balance

That leaves a rate gap of about 2.42, which tells you how far the mixture still is from a balanced exchange.

Current balance

Forward change is still winning, so the mixture is moving toward more products.

Common misconception

If the amounts stop changing, the reaction itself must have stopped.

The amounts can stay steady because forward and reverse change match each other.

The microscopic exchange can continue even while the overall mixture looks settled.

Mini challenge

Disturb the mixture, then wait until the rates nearly match again while the settled mix is clearly product-favored.

Make a prediction before you reveal the next step.

Decide whether you should change the starting mixture, the favor setting, or both before you test it.

Check your reasoning against the live bench.

You need a disturbance that pushes the system away from its old balance and conditions that favor the product side strongly enough for the new equilibrium to land there.
That shows both halves of the idea at once: the equilibrium is dynamic because the exchange continues, and Le Chatelier's principle is about the path to a new balance after a disturbance.

Quick test

Misconception check

Question 1 of 3

Answer from the live equilibrium story, not from a slogan about the reaction being finished.

What is the cleanest description of dynamic equilibrium?

Use the live bench to test the result before moving on.

Accessibility

The simulation shows a reversible chemistry bench with reactants and products visible at the same time, plus pulse cues for forward and reverse change and balance bars for the current rates. Sliders change the starting amounts and the product-favor setting.

A readout card reports the current reactant amount, product amount, forward rate, reverse rate, and settled product share so the learner can compare the moving bench with the graphs.

Graph summary

One graph shows the reactant and product amounts over time, a second compares the forward and reverse rates over time, and a third shows the settled product share against the product-favor setting.

Graph hover, compare mode, and the shared overlays all stay attached to the same chemistry bench and do not open a separate chemistry-only view.