Molar mass is the mass of a substance that has 6.022 × 1023 atoms (Avogadro's number). The mass number of an element is equal to the molar mass of the element . The molar mass of a chemical compound is the mass when the compound has 6.022 × 1023 molecules. Molar mass of Chlorine is 35.45 due to consideration of avg molar mass by including mass of its all isotopes.
It can be found by adding the molar masses of all of its elements. Sodium hydroxide's (NaOH) molar mass can be found by adding the molar mass of sodium, oxygen, and hydrogen, which would be 39.997 g/mo