Formula mass, molar mass and Avagadro's number.
Step-by-step explanation:
number of atoms in a compound can be calculated by knowing the molar mass of the compound or element, the result will be multiplied by avagadro's number (6.022*10^23)
1 mole of a substance is equal to Avagadro number of atoms.
If the number of moles is known of a compound or element its molar mass can be calculated as:
n= Weight of the compound/element given/ molecular weight of the same.
formula mass is the mass of compound ie chemical compound formed with different molecules. its mass is calculated by adding the molar masses of all the elements taking part in its assembly.