Chemistry · Chapter 3

Molar Mass, Atom by Atom

Type any formula and watch the sum build itself. Parentheses multiply the whole group inside them, and a raised dot adds water that is locked into the crystal.

Type a formula try brackets and dots

Capital letters start an element. A number after a symbol or a bracket is a subscript. Write a hydrate with a dot, as in CuSO4.5H2O or CuSO₄·5H₂O.

The sum one row per element

164.09g/mol parsed
ElementAtomsAtomic massMass addedShare
Total9164.086100%

Share of the mass

Each element's share of the molar mass

Width shows the mass each element brings, not how many atoms it has. A single heavy atom can outweigh many light ones.

Put it to work

Left box is grams. Right box is moles. Type in one and the other follows, using the molar mass above as the factor.

What to notice

Oxygen is light on its own, yet compounds with many oxygens often carry most of their mass in oxygen. Count the atoms inside brackets before you add.