Do formula mass and molar mass mean the same thing?
formula mass and molar mass are the same concept but applied to covalent and ionic substances.
Covalent compound have molar masses. this is the sum of all the atoms that make up a mole of the compound.
Ionic compounds do not actually form molecules but interlocking ionic lattice structures. The formula mass is the mass of one mole of the simplest crystal unit of the lattice.
Both formula mass and molar mass refer to the mass of a mole of atoms that make up the basic unit of the compound. In molar mass the atoms are usually joined in a molecule, In formula mass the atoms are the simplest formula unit in a complex lattice.