Is 3H2O three molecules or three moles of water?

The notation of the form “3H2O” denotes three molecules of a complex substance – water (H2O), consisting of two hydrogen atoms (H) and one oxygen atom (O). The number of moles is indicated by the Latin letter “nu” (ν), it can be found by dividing the mass of a substance by its molar mass. Various coefficients in front of the formulas of substances are often put in the equations of chemical reactions in order to equalize the number of atoms of each chemical element on the right and left sides of the equation, only in this form most of the equations of chemical reactions are correct.