In short
A chemical formula shows the elements in a compound and how many atoms of each there are. A chemical equation shows a reaction, with the reactants on the left and the products on the right.
An equation must be balanced: each element has the same number of atoms on both sides, because atoms are not made or lost. Balance by changing the large numbers in front of formulae, the coefficients, never the small numbers inside a formula. State symbols show the state: (s) solid, (l) liquid, (g) gas and (aq) dissolved in water.
Methane burning: . Left: 1 C, 4 H, 4 O. Right: 1 C, 4 H, O. It is balanced.
Also searched as: chemical formula search.
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