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Chemical Formulas: How to Represent Compounds
- Compounds have constant composition with respect to mass because they are composed of atoms in fixed ratios.
- A chemical formula indicates the elements present in a compound and the relative number of atoms of each.
- For example, H2O is the chemical formula for water; it indicates that water consists of hydrogen and oxygen atoms in a 2:1 ratio.
- The formula contains the symbol for each element, accompanied by a subscript indicating the number of atoms of that element. By convention, a subscript of 1 is omitted.