Chemical Equations

Arrows mean 'Change into'
E.g. Hydrogen + Oxygen --> Water (Word Equation)
2H2 + O2 --> 2H2O (Chemical Equation)

Chemical symbols
Writing word equations is often not practical. To avoid this, scientists assign a symbol to each element.

Writing chemical equations
Word equations adequately describe chemical equations, but are cumbersome. As a result, we use chemical equations. In a chemical equation, an arrow separates the formulas of the reactants (on the left) from the formulas products (on the right).

Equations that show only show the formulas of the reactants and the products are called skeletal equations. A skeleton equation does not indicate the relative amounts of reactants and products or the state of them. The state of the products and reactants is indicated by putting the symbol into the formula, three states of matter (g), (s), (l). A fourth state is used to indicate if a product or a reactant is in an aqueous (aq) (water).

*A catalyst is written above the arrow, only if it is involved in a reaction.