How do you calculate atoms of an element?

1 Answer
Jun 16, 2014

There are two ways to look at this question
One is the question asking "how do you calculate the atoms of an element within a given compound?"

Let us use water as an example. Examine the chemical formula of water, H2O. The formula tells that the subscript 2 means that there are two hydrogen atoms in one water molecule and one oxygen atom in one water molecule. The subscript is not normally written; it is implied.

The second way to look at this question "How do you calculate the number of atoms of an element in a given number of moles.

A mole is equal to Avogadro's number which is 6.02x1023
atoms.

If you look at the atomic weight of hydrogen, one mole equals the atomic weight as well. So that means in 1.0 grams of hydrogen, you have 6.02x1023 hydrogen atoms.