Molecular Mass

Calculate the relative mass of a molecule or salt and the number of protons and atoms from its chemical formula. Please enter the formula with the common element symbols, numbers not subscripted. The molecules may contain the elements 1 - 96 (hydrogen - curium, H - Cm), as well as deuterium (D). Brackets can't be processed, spaces are ignored. It won't be checked, if the according molecule exists or is possible. For the masses of the single elements, see atomic masses.
Examples for possible formulas are H2O for water, AgNO3 for silver nitrate and C72 H100 Co N18 O17 P for vitamin B12. The latter molecule has a mass of 1579.59 u and contains a total of 836 protons, 209 atoms and 6 different atoms.

The molecular mass is calculated from the mass of the atoms it contains. Likewise, the number of protons is determined from the atomic numbers of the atoms involved. To determine the number of atoms, the indices of the elements are simply added together; where no index are given, the index is 1. However, the number of protons and the number of atoms are unique; the molecular mass is an average value and can vary slightly for specific molecules depending on the isotopes involved. For the number of each atom, see atoms counter.

Molecular mass is different from molar mass, but is closely related. Both have the same numerical value but a different unit. Molar mass is expressed in grams per mole. The unit of molecular mass, u, stands for unified atomic mass unit. 1 u is defined as one-twelfth the mass of the isotope C¹². A mole, on the other hand, is a number of particles; the number is Avogadro's constant 6.02214076*10²³. This number of particles with molecular mass x u has a mass of x grams; the molar mass is x grams per mole.