A chemical reaction can be described in several different ways. For the given reaction, different forms are:
1. When one mole of magnesium is burned, it forms magnesium oxide and releases 39.2 J of energy (chemical information in words).
2. One gram-atom metallic magnesium burns in air with bright flames to produce one mole of white magnesium oxide and 39.2 J heat energy (representation stating stoichiometry in moles).
3. When 24.3 g metallic magnesium is burned in presence of sufficient amount of oxygen, 40.3 g magnesium oxide and 39.2 heat energy is produced (chemical information in words, stating stoichiometry in grams).
4. Mg + ½ O2 -> MgO + 39.2 J (energy)