Chemistry

How do you balance a chemical equation?

Quick answer

Balancing a chemical equation means making the number of atoms of each element the same on both sides, because matter is conserved in a reaction.

Step 1: Write the unbalanced equation with correct formulas. Step 2: Count the atoms of each element on both sides. Step 3: Add coefficients (never change subscripts) to equalise the counts — balance metals first, then non-metals, and hydrogen and oxygen last. Step 4: Check that every element balances and the coefficients are in the smallest whole-number ratio.

Example: H₂ + O₂ → H₂O becomes 2H₂ + O₂ → 2H₂O. Now there are 4 H and 2 O on each side.

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