Tom Skerritt. Biography: Tom Skerritt is probably the best-known actor whose name is never remembered. A rugged outdoors type, Skerritt briefly attended Wayne State University and UCLA before making his film bow in [[Feature~V115961~War Hunt~warhunt]] (1962). His...
The chemical formula for oxygen is O2 and for individual oxygen  atom its symbol is O.   Gases such as oxygen exist as diatomic molecules.
Water is represented by the empirical formula H2O, denoting that the substance contains two atoms of hydrogen (H2) for every atom of oxygen (O). A general formula is a type of empirical formula that represents the composition of any member of an entire class of compounds.