Mass Ratio

Here the ratio of the masses of molecules or atoms can be calculated. Please enter the empirical formula of two molecules, the input format is similar to the molecular mass calculator, like H2O for water. The amount of each molecule can be specified; if this is omitted, 1 is assumed as the amount. Several molecules can also be entered consecutively in each input field. Both molecular masses and the ratios to each other will be calculated.

Examples: For the water molecule H₂O, the input at x is 1 H2 and at y is 1 O for the ratio of the two components of this molecule. Here, the mass ratio of oxygen to hydrogen is 7.94. Therefore, even though it contains two hydrogen atoms and only one oxygen atom, oxygen is present with almost eight times the mass.
For air, which is approximately 78.1 percent nitrogen (N₂) and 20.9 percent oxygen (O₂), the input is 78.1 N2 and 20.9 O2. Here, the calculated ratio is 3.27. Unlike water, air is not a single molecule, but is composed largely of nitrogen molecules and oxygen molecules. However, this calculation does not change whether the different substances are components of a molecule or not.

The unit u is the unified atomic mass unit. One u is defined as one twelfth of the mass of the carbon isotope C¹². Protons and neutrons each have a mass of approximately 1 u. The neutron is slightly heavier, and the exact mass of neutrons and protons also depends on the atomic nucleus in which they are located. However, chemical elements have masses with values ​​that are fractions of u primarily because they are composed of various naturally occurring isotopes; these mass specifications are therefore average values. For the masses of individual elements, see atomic masses.