The molar mass of a substance is the mass of one mole of that substance, so the question is asking you how many moles of carbon atoms are in 0.62g of this substance. If you had a 0.62g sample of carbon atoms, then the molar mass would be the mass of 0.
The mole is a unit of measurement that expresses the number of atoms in a given amount of a substance. One mole of a substance contains 6.02 x 10^23 atoms of that substance.
The mass of 0.62g is equal to the formula mass of C in grams. The formula for carbon is C, with a mass number of 12. The number of moles of C atoms in 0.62g is given by the formula: formula_1 where: formula_1 = 0.62 / 12 = 0.