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Balancing chemical equations

Change the coefficients to find the minimum integer ratio that preserves the number of atoms for each element.

    C11 · Balancing chemical equationsReady
    Change the coefficients to find the minimum integer ratio that preserves the number of atoms for each element. You can also experiment with the numbers and controls below.

    Chemistry · Reaction formula · Quantitative relationships / Principles and exploration

    Balancing chemical equations — principles and investigation

    In a chemical reaction, new atoms are not created or lost, so the number of atoms for each element before and after the reaction must be the same. Select a reaction equation and adjust the coefficients in front of each substance. This activity distinguishes between subscript modification, which changes the substance itself, and coefficient adjustment, which adjusts the number of atoms.

    How does it work?

    The subscripts in the chemical formula are not changed, but only the coefficients are adjusted. If you preserve the number of atoms and then divide the coefficient by the greatest common divisor, you get the minimum integer ratio.

    Key relationship

    Number of atoms before reaction of each element = Number of atoms after reaction

    Try this investigation

    1. Choose one of five responses and change the coefficient sliders or direct input. The coefficients are the number of groups of molecules or chemical units, and the bars for each element are the number of atoms. Determine with the atomic number check button.
    2. Check and record the 1:1:1 and 2:1:2 hydrogen reactions, respectively. Even the meals that do not match are recorded as comparative data.
    3. Record the cases where the hydrogen reaction was increased to 4:2:4 and the propane combustion was adjusted to 1:5:3:4. Try solving the remaining examples yourself.

    Interpreting your results

    What is the minimum whole number ratio between 2H₂ + O₂ → 2H₂O and 4H₂ + 2O₂ → 4H₂O?

    In both formulas, the number of atoms per element is the same, but 4:2:4 can be divided by the common divisor of 2. Use a ratio where the greatest common divisor of positive integer coefficients is 1.

    Assumptions and limitations

    It is a model that counts the number of atoms in five specified reactions. The particle picture refers to a bundle of molecules or chemical formula units and does not mean that iron and iron oxide exist as independent molecules. The bonding structure, reaction conditions, reaction rate, and yield are not calculated. The unit of numbers in bars and tables is the number of atoms.