How to determine the moles of a compound using volume?

I assume you mean, how to calculate the moles in a substance from grams.

Firstly, you will need to take into account the mass number of the atoms in the molecular compound.

Say, H2O.

Hydrogen mass = 1.00794

Oxygen mass = 15.9994

I will then have to multiply the atoms by their quantities and combine the molecular compound atoms' mass, respectively.

(2) (1.00794) + (1) (15.9994) = 18.01528.

This is used as the divisor that is divided to grams, to find the moles of a substance.

For example, 10 grams is 10/18.01528 = 0.56 moles