What is formula mass and how is it calculated?

1 Answer
anor277
Jun 7, 2016

The formula mass of a molecule or species is simply the sum of the atomic masses of the constituent atoms in the formula of the compound.

Explanation:

The units of formula mass are thus g*mol^-1, or, more fundamentally, "amu "=" atomic mass units". As chemists, we typically deal with molar quantities, so units of g*mol^-1 are appropriate.

So let's try to calclate the formula mass of Na_2SO_4 in g*mol^-1.

"Formula mass " Na_2SO_4 = (2xx22.99+32.06+4xx15.999)*g*mol^-1=??g*mol^-1. From where did I get those numbers?

Related questions
See all questions in Atomic Mass
Impact of this question
2445 views around the world
You can reuse this answer
Creative Commons License