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Enter an unbalanced equation:

Result:

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How to use the calculator

Enter a chemical equation in the input field above. Example: Fe + O2 = Fe2O3. Click "Balance" to see the balanced equation.

Formula & Equation Used

The calculator sets up a system of linear equations for each element:

Σ(coefficients×atoms of element in compound) = same on both sides of the equation
  • coefficients: unknown integers that multiply each chemical species in the equation
  • atoms of element in compound: number of atoms of each element in each compound

Example Problem & Step-by-Step Solution

Problem:

Balance the chemical equation: Fe + O2 = Fe2O3

Solution:

  1. Assign coefficients: a Fe + b O2 = c Fe2O3
  2. Write balance equations for each element:
Fe: a = 2c (1) O: 2b = 3c (2)
  1. Choose the smallest whole number for c to solve the equations: Let c = 1, then from (1) a = 2 and from (2) 2b = 3 → b = 3/2
  2. To eliminate fraction, multiply all coefficients by 2: a = 4, b = 3, c = 2
  3. Write balanced equation: 4 Fe + 3 O2 = 2 Fe2O3
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