Molar mass is the mass of one mole of a substance. In order to determine the molar mass of a substance, the atomic weight from the periodic table is used, but is written as grams/mole. The atomic weight in grams for each element is multiplied times the subscript for that element. Then all of the results are added together to get the molar mass of the substance.
Calculate the molar mass of ethyne,
Carbon: 12.011g/mol x 2 = 24.022g/mol
Hydrogen: 1.008g/mol x 2 = 2.016g/mol
The molar mass of