To calculate the molar mass of H3PO4 $phosphoricacid$, we need to first determine the total number of atoms present in the molecule and then multiply by the individual atomic masses.

H3PO4 contains:

3 atoms of hydrogen $H$, each with a molar mass of 1
1 atom of phosphorus $P$, with a molar mass of approximately 31
4 atoms of oxygen $O$, each with a molar mass of 16

Adding these together:

$3x1$ + 31 + $4x16$ = 3 + 31 + 64
= 98

Therefore, the molar mass of phosphoric acid $H3PO4$ is 98 g/mol.