Chemical formula that compound will be made up of the same elements in the same proportion or ratio. For example, any water molecule is always made up of two hydrogen atoms and one oxygen atom in a 2:1 ratio. If we look at the relative masses of oxygen and hydrogen in a water molecule, we see that 94% of the mass of a water molecule is accounted for by oxygen and the remaining 6% is the mass of hydrogen. This mass proportion will be the same for any water molecule. The alkene called but-2-ene has two isomers, which the chemical formula CHCH=CHCH
Chemical formula does not identify. The relative position of the two methyl groups must be indicated by additional notation denoting whether the methyl groups are on the same side of the double bond ("cis" or "Z") or on the opposite sides from each other ("trans" or "E"). Such extra symbols violate the rules for chemical formulas, and begin to enter the territory of more complex naming systems. As noted above, in order to represent the full structural formulas of many complex organic and inorganic compounds, chemical nomenclature may be needed which goes well beyond the available resources used above in simple condensed