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Limiting reactants

Check the limiting reactant, production amount, and mass conservation using the number of moles of input and coefficient.

    C12 · Limiting reactantsReady
    Check the limiting reactant, production amount, and mass conservation using the number of moles of input and coefficient. You can also experiment with the numbers and controls below.

    Chemistry · Reaction formula · Quantitative relationships / Principles and exploration

    Limiting reactants — principles and investigation

    Even if you add a lot of two reactants, it doesn't mean that both react to the end. Find the limiting reactant consumed first by comparing the coefficient ratio in the reaction equation and the number of moles input. Not only the amount of product but also the remaining reactant must be included to correctly compare the mass before and after the reaction.

    How does it work?

    The limiting reactant determines the amount produced. After a reaction, both the products and remaining reactants must be included to preserve mass.

    Key relationship

    ξ = min(nᵢ/νᵢ) · Remaining amount = nᵢ−νᵢξ · Amount produced = νproductξ

    Try this investigation

    1. Select the reaction equation and the two moles of input and run it. Check the mass by counting the product and remaining material together. If n/ν is the same, both reactants are consumed together.
    2. Maintain 3 mol of H₂ and execute and record 1 mol and 2 mol of O₂ respectively.
    3. Record the conditions in which only O₂ was changed to 1.5 mol, the number of moles input was kept at the standard value, and only the reaction formula was changed to ammonia synthesis.

    Interpreting your results

    What value is the limiting reactant set to?

    We need to compare the number of moles divided by the coefficient ν in the reaction equation. H₂ is 3/2=1.5 mol, O₂ is 1/1=1 mol, so ξ=1 mol and 2 mol of water is produced.

    Assumptions and limitations

    Assume that the three reactions are completed without any side reactions. Equilibrium, speed, and actual yield are excluded. Molar mass is calculated using educational atomic weights of H=1, C=12, N=14, and O=16 g/mol. The circle is a schematic diagram of a bundle of moles, not the actual number of molecules. The unit of ξ is mol.