The document provides instructions on writing chemical formulas and equations. It defines the components of a formula, such as lithium carbonate (Li2CO3), and states that diatomic elements like hydrogen (H2) exist as discrete units. The text then explains the components of a chemical equation, including reactants, products, and states of matter (s, l, g, aq). Sample equations are given that show hydrogen gas and oxygen gas reacting to form liquid water, and sodium metal with water forming sodium hydroxide and hydrogen gas.