To balance a chemical equation we need to make sure we have the same number of each type of atom on both sides of the equation. We can't change the proportion of atoms in a molecule because this would change the compound, but we can change the number of molecules involved in the reaction. We do this by adding a number in front of the molecules. There is no straight forward method to do this, it comes down to trial and error.
For each word equation, balance the chemical equation and add state symbols. Insert 1's where we would normally leave it blank.
