Limiting Reactant Visualizer

Instructions

Choose how many moles of each reactant to start with, predict which one runs out, then watch the molecules pair up into products. Whatever is left over has nothing to react with.

  1. Choose the reaction and starting amounts, then predict the limiting reactant.
  2. Run the reaction and compare the particles with the before, change, and after table.
  3. Identify the excess reactant and explain what limits the amount of product.

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3. Watch the molecules

The reaction box

4. Track the moles

Before, change, after

Amounts in mol. After and the molecule counts update as each reaction happens.

5. Explain

Why did it stop?

6. Check your thinking

Test each idea in the box

7. Make sense of it

What decides how much product forms?

Try a box where you have more of the reactant that runs out first, and one with the exact ratio of the equation.

Why did the reaction stop while some molecules were still there? Is the limiting reactant always the one you have less of? What would adding more of the excess reactant do?

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About this activity

Choose starting amounts of two reactants and watch the molecules pair up into products. See which reactant runs out first and how much of the other is left over.

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