Balanced symbol equations

No atoms are created or destroyed in a chemical reaction – they are just rearranged.

Balanced symbol equations show the original arrangements and the new ones.

Copper (II) oxideNo atoms are created or destroyed when copper reacts with oxygen to form copper(II) oxide

Writing balanced symbol equations

StepResult
Check to see if there is an equal number of atoms of each element on both sides. There is not.N2 + H2 → NH3
There are two nitrogen atoms on the left but only one on the right, so put a big 2 on the left of the NH3.N2 + H2 → 2NH3
Check again. There are two hydrogen atoms on the left but (2 × 3) = 6 on the right, so put a big 3 in front of the H2.N2 + 3H2 → 2NH3
Check again to see if there are equal numbers of each element on both sides. There is.(Two nitrogen atoms and six hydrogen atoms)
Add the state symbols if asked to do so.N2(g) + 3H2(g) → 2NH3(g)
curriculum-key-fact
A balancing number multiplies all the atoms in the formula next to it. Never change the formula of a compound to make the equation balance.