The molar mass of argon is approximately 39.95 g/mol. This value represents the mass of one mole of argon atoms, which is a noble gas and is found in Group 18 of the periodic table.
To understand why the molar mass is 39.95 g/mol, it is important to note that this figure is based on the weighted average of all naturally occurring isotopes of argon. Argon has three stable isotopes: Argon-36, Argon-38, and Argon-40, with Argon-40 being the most abundant. The atomic weight given on the periodic table reflects this weighted average, giving us the value of approximately 39.95 g/mol.