The molar mass of C6H6, which is the chemical formula for benzene, is 78.11 grams per mole. The molar mass of a compound is calculated by adding together the atomic mass of each atom it contains.
The atomic mass of carbon, represented by the chemical symbol C, is 12.01 grams per mole. For the six total atoms of carbon in benzene, the total mass is 72.06 grams per mole. The atomic mass of hydrogen, represented by the chemical symbol H, is about 1 gram per mole, for a total mass of about 6 grams per mole in the compound for benzene.