Balance this equation: H₂ + O₂ → H₂O. How many molecules of each are needed?
Hints
You need 2 oxygen atoms on the left to match the oxygen in water molecules.
Answer
2 H₂ + O₂ → 2 H₂O. Two hydrogen molecules plus one oxygen molecule produces two water molecules. This balances 4 hydrogen atoms and 2 oxygen atoms on each side.